Merge pull request #30634 from smoogipoo/multiplayer-remove-cmc-and-composite

Remove `CachedModelDependencyContainer` and `OnlinePlayComposite` from multiplayer

osu.Android.props

@@ -10,7 +10,7 @@
     <EmbedAssembliesIntoApk>true</EmbedAssembliesIntoApk>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="ppy.osu.Framework.Android" Version="2024.1115.0" />
+    <PackageReference Include="ppy.osu.Framework.Android" Version="2024.1118.0" />
   </ItemGroup>
   <PropertyGroup>
     <!-- Fody does not handle Android build well, and warns when unchanged.

osu.Game.Tests/NonVisual/Multiplayer/StatefulMultiplayerClientTest.cs

@@ -75,7 +75,7 @@ namespace osu.Game.Tests.NonVisual.Multiplayer
                 var newRoom = new Room();
                 newRoom.CopyFrom(SelectedRoom.Value);
 
-                newRoom.RoomID.Value = null;
+                newRoom.RoomID = null;
                 MultiplayerClient.RoomSetupAction = room =>
                 {
                     room.State = MultiplayerRoomState.Playing;

osu.Game.Tests/Visual/DailyChallenge/TestSceneDailyChallenge.cs

@@ -39,18 +39,18 @@ namespace osu.Game.Tests.Visual.DailyChallenge
         {
             var room = new Room
             {
-                RoomID = { Value = 1234 },
-                Name = { Value = "Daily Challenge: June 4, 2024" },
+                RoomID = 1234,
+                Name = "Daily Challenge: June 4, 2024",
                 Playlist =
-                {
+                [
                     new PlaylistItem(TestResources.CreateTestBeatmapSetInfo().Beatmaps.First())
                     {
                         RequiredMods = [new APIMod(new OsuModTraceable())],
                         AllowedMods = [new APIMod(new OsuModDoubleTime())]
                     }
-                },
-                EndDate = { Value = DateTimeOffset.Now.AddHours(12) },
-                Category = { Value = RoomCategory.DailyChallenge }
+                ],
+                EndDate = DateTimeOffset.Now.AddHours(12),
+                Category = RoomCategory.DailyChallenge
             };
 
             AddStep("add room", () => API.Perform(new CreateRoomRequest(room)));
@@ -62,18 +62,18 @@ namespace osu.Game.Tests.Visual.DailyChallenge
         {
             var room = new Room
             {
-                RoomID = { Value = 1234 },
-                Name = { Value = "Daily Challenge: June 4, 2024" },
+                RoomID = 1234,
+                Name = "Daily Challenge: June 4, 2024",
                 Playlist =
-                {
+                [
                     new PlaylistItem(TestResources.CreateTestBeatmapSetInfo().Beatmaps.First())
                     {
                         RequiredMods = [new APIMod(new OsuModTraceable())],
                         AllowedMods = [new APIMod(new OsuModDoubleTime())]
                     }
-                },
-                EndDate = { Value = DateTimeOffset.Now.AddHours(12) },
-                Category = { Value = RoomCategory.DailyChallenge }
+                ],
+                EndDate = DateTimeOffset.Now.AddHours(12),
+                Category = RoomCategory.DailyChallenge
             };
 
             AddStep("add room", () => API.Perform(new CreateRoomRequest(room)));
@@ -91,18 +91,18 @@ namespace osu.Game.Tests.Visual.DailyChallenge
         {
             var room = new Room
             {
-                RoomID = { Value = 1234 },
-                Name = { Value = "Daily Challenge: June 4, 2024" },
+                RoomID = 1234,
+                Name = "Daily Challenge: June 4, 2024",
                 Playlist =
-                {
+                [
                     new PlaylistItem(TestResources.CreateTestBeatmapSetInfo().Beatmaps.First())
                     {
                         RequiredMods = [new APIMod(new OsuModTraceable())],
                         AllowedMods = [new APIMod(new OsuModDoubleTime())]
                     }
-                },
-                EndDate = { Value = DateTimeOffset.Now.AddHours(12) },
-                Category = { Value = RoomCategory.DailyChallenge }
+                ],
+                EndDate = DateTimeOffset.Now.AddHours(12),
+                Category = RoomCategory.DailyChallenge
             };
 
             AddStep("add room", () => API.Perform(new CreateRoomRequest(room)));

osu.Game.Tests/Visual/DailyChallenge/TestSceneDailyChallengeCarousel.cs

@@ -26,11 +26,6 @@ namespace osu.Game.Tests.Visual.DailyChallenge
 
         private readonly Bindable<Room> room = new Bindable<Room>(new Room());
 
-        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent) => new CachedModelDependencyContainer<Room>(base.CreateChildDependencies(parent))
-        {
-            Model = { BindTarget = room }
-        };
-
         [Test]
         public void TestBasicAppearance()
         {
@@ -98,7 +93,7 @@ namespace osu.Game.Tests.Visual.DailyChallenge
                                 Origin = Anchor.Centre,
                                 Children = new Drawable[]
                                 {
-                                    new DailyChallengeTimeRemainingRing(),
+                                    new DailyChallengeTimeRemainingRing(room.Value),
                                     breakdown = new DailyChallengeScoreBreakdown(),
                                 }
                             }
@@ -125,8 +120,8 @@ namespace osu.Game.Tests.Visual.DailyChallenge
             AddSliderStep("update time remaining", 0f, 1f, 0f, progress =>
             {
                 var startedTimeAgo = TimeSpan.FromHours(24) * progress;
-                room.Value.StartDate.Value = DateTimeOffset.Now - startedTimeAgo;
-                room.Value.EndDate.Value = room.Value.StartDate.Value.Value.AddDays(1);
+                room.Value.StartDate = DateTimeOffset.Now - startedTimeAgo;
+                room.Value.EndDate = room.Value.StartDate.Value.AddDays(1);
             });
             AddStep("add normal score", () =>
             {

osu.Game.Tests/Visual/DailyChallenge/TestSceneDailyChallengeIntro.cs

@@ -68,19 +68,19 @@ namespace osu.Game.Tests.Visual.DailyChallenge
             {
                 API.Perform(new CreateRoomRequest(room = new Room
                 {
-                    RoomID = { Value = roomId },
-                    Name = { Value = "Daily Challenge: June 4, 2024" },
+                    RoomID = roomId,
+                    Name = "Daily Challenge: June 4, 2024",
                     Playlist =
-                    {
+                    [
                         new PlaylistItem(CreateAPIBeatmap(new OsuRuleset().RulesetInfo))
                         {
                             RequiredMods = [new APIMod(new OsuModTraceable())],
                             AllowedMods = [new APIMod(new OsuModDoubleTime())]
                         }
-                    },
-                    StartDate = { Value = DateTimeOffset.Now },
-                    EndDate = { Value = DateTimeOffset.Now.AddHours(24) },
-                    Category = { Value = RoomCategory.DailyChallenge }
+                    ],
+                    StartDate = DateTimeOffset.Now,
+                    EndDate = DateTimeOffset.Now.AddHours(24),
+                    Category = RoomCategory.DailyChallenge
                 }));
             });
             AddStep("signal client", () => metadataClient.DailyChallengeUpdated(new DailyChallengeInfo { RoomID = roomId }));

osu.Game.Tests/Visual/DailyChallenge/TestSceneDailyChallengeLeaderboard.cs

@@ -43,7 +43,7 @@ namespace osu.Game.Tests.Visual.DailyChallenge
                     return false;
                 };
             });
-            AddStep("create leaderboard", () => Child = leaderboard = new DailyChallengeLeaderboard(new Room { RoomID = { Value = 1 } }, new PlaylistItem(Beatmap.Value.BeatmapInfo))
+            AddStep("create leaderboard", () => Child = leaderboard = new DailyChallengeLeaderboard(new Room { RoomID = 1 }, new PlaylistItem(Beatmap.Value.BeatmapInfo))
             {
                 RelativeSizeAxes = Axes.Both,
                 Anchor = Anchor.Centre,
@@ -86,7 +86,7 @@ namespace osu.Game.Tests.Visual.DailyChallenge
                     return false;
                 };
             });
-            AddStep("create leaderboard", () => Child = leaderboard = new DailyChallengeLeaderboard(new Room { RoomID = { Value = 1 } }, new PlaylistItem(Beatmap.Value.BeatmapInfo))
+            AddStep("create leaderboard", () => Child = leaderboard = new DailyChallengeLeaderboard(new Room { RoomID = 1 }, new PlaylistItem(Beatmap.Value.BeatmapInfo))
             {
                 RelativeSizeAxes = Axes.Both,
                 Anchor = Anchor.Centre,

osu.Game.Tests/Visual/DailyChallenge/TestSceneDailyChallengeTimeRemainingRing.cs

@@ -18,11 +18,6 @@ namespace osu.Game.Tests.Visual.DailyChallenge
     {
         private readonly Bindable<Room> room = new Bindable<Room>(new Room());
 
-        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent) => new CachedModelDependencyContainer<Room>(base.CreateChildDependencies(parent))
-        {
-            Model = { BindTarget = room }
-        };
-
         [Cached]
         private OverlayColourProvider colourProvider = new OverlayColourProvider(OverlayColourScheme.Plum);
 
@@ -38,7 +33,7 @@ namespace osu.Game.Tests.Visual.DailyChallenge
                     RelativeSizeAxes = Axes.Both,
                     Colour = colourProvider.Background4,
                 },
-                ring = new DailyChallengeTimeRemainingRing
+                ring = new DailyChallengeTimeRemainingRing(room.Value)
                 {
                     RelativeSizeAxes = Axes.Both,
                     Anchor = Anchor.Centre,
@@ -59,29 +54,29 @@ namespace osu.Game.Tests.Visual.DailyChallenge
 
             AddStep("just started", () =>
             {
-                room.Value.StartDate.Value = DateTimeOffset.Now.AddMinutes(-1);
-                room.Value.EndDate.Value = room.Value.StartDate.Value.Value.AddDays(1);
+                room.Value.StartDate = DateTimeOffset.Now.AddMinutes(-1);
+                room.Value.EndDate = room.Value.StartDate.Value.AddDays(1);
             });
             AddStep("midway through", () =>
             {
-                room.Value.StartDate.Value = DateTimeOffset.Now.AddHours(-12);
-                room.Value.EndDate.Value = room.Value.StartDate.Value.Value.AddDays(1);
+                room.Value.StartDate = DateTimeOffset.Now.AddHours(-12);
+                room.Value.EndDate = room.Value.StartDate.Value.AddDays(1);
             });
             AddStep("nearing end", () =>
             {
-                room.Value.StartDate.Value = DateTimeOffset.Now.AddDays(-1).AddMinutes(8);
-                room.Value.EndDate.Value = room.Value.StartDate.Value.Value.AddDays(1);
+                room.Value.StartDate = DateTimeOffset.Now.AddDays(-1).AddMinutes(8);
+                room.Value.EndDate = room.Value.StartDate.Value.AddDays(1);
             });
             AddStep("already ended", () =>
             {
-                room.Value.StartDate.Value = DateTimeOffset.Now.AddDays(-2);
-                room.Value.EndDate.Value = room.Value.StartDate.Value.Value.AddDays(1);
+                room.Value.StartDate = DateTimeOffset.Now.AddDays(-2);
+                room.Value.EndDate = room.Value.StartDate.Value.AddDays(1);
             });
             AddSliderStep("manual progress", 0f, 1f, 0f, progress =>
             {
                 var startedTimeAgo = TimeSpan.FromHours(24) * progress;
-                room.Value.StartDate.Value = DateTimeOffset.Now - startedTimeAgo;
-                room.Value.EndDate.Value = room.Value.StartDate.Value.Value.AddDays(1);
+                room.Value.StartDate = DateTimeOffset.Now - startedTimeAgo;
+                room.Value.EndDate = room.Value.StartDate.Value.AddDays(1);
             });
         }
     }

osu.Game.Tests/Visual/Menus/TestSceneMainMenu.cs

@@ -42,14 +42,14 @@ namespace osu.Game.Tests.Visual.Menus
                         beatmap.OnlineID = 1001;
                         getRoomRequest.TriggerSuccess(new Room
                         {
-                            RoomID = { Value = 1234 },
-                            Name = { Value = "Aug 8, 2024" },
+                            RoomID = 1234,
+                            Name = "Aug 8, 2024",
                             Playlist =
-                            {
+                            [
                                 new PlaylistItem(beatmap)
-                            },
-                            StartDate = { Value = DateTimeOffset.Now.AddMinutes(-30) },
-                            EndDate = { Value = DateTimeOffset.Now.AddSeconds(60) }
+                            ],
+                            StartDate = DateTimeOffset.Now.AddMinutes(-30),
+                            EndDate = DateTimeOffset.Now.AddSeconds(60)
                         });
                         return true;
 

osu.Game.Tests/Visual/Multiplayer/QueueModeTestScene.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Allocation;
@@ -30,16 +28,16 @@ namespace osu.Game.Tests.Visual.Multiplayer
     {
         protected abstract QueueMode Mode { get; }
 
-        protected BeatmapInfo InitialBeatmap { get; private set; }
-        protected BeatmapInfo OtherBeatmap { get; private set; }
+        protected BeatmapInfo InitialBeatmap { get; private set; } = null!;
+        protected BeatmapInfo OtherBeatmap { get; private set; } = null!;
 
         protected IScreen CurrentScreen => multiplayerComponents.CurrentScreen;
         protected IScreen CurrentSubScreen => multiplayerComponents.MultiplayerScreen.CurrentSubScreen;
 
-        private BeatmapManager beatmaps;
-        private BeatmapSetInfo importedSet;
+        private BeatmapManager beatmaps = null!;
+        private BeatmapSetInfo importedSet = null!;
 
-        private TestMultiplayerComponents multiplayerComponents;
+        private TestMultiplayerComponents multiplayerComponents = null!;
 
         protected TestMultiplayerClient MultiplayerClient => multiplayerComponents.MultiplayerClient;
 
@@ -75,15 +73,15 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddUntilStep("wait for lounge", () => multiplayerComponents.ChildrenOfType<LoungeSubScreen>().SingleOrDefault()?.IsLoaded == true);
             AddStep("open room", () => multiplayerComponents.ChildrenOfType<LoungeSubScreen>().Single().Open(new Room
             {
-                Name = { Value = "Test Room" },
-                QueueMode = { Value = Mode },
+                Name = "Test Room",
+                QueueMode = Mode,
                 Playlist =
-                {
+                [
                     new PlaylistItem(InitialBeatmap)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                }
+                ]
             }));
 
             AddUntilStep("wait for room open", () => this.ChildrenOfType<MultiplayerMatchSubScreen>().FirstOrDefault()?.IsLoaded == true);
@@ -98,7 +96,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         [Test]
         public void TestCreatedWithCorrectMode()
         {
-            AddUntilStep("room created with correct mode", () => MultiplayerClient.ClientAPIRoom?.QueueMode.Value == Mode);
+            AddUntilStep("room created with correct mode", () => MultiplayerClient.ClientAPIRoom?.QueueMode == Mode);
         }
 
         protected void RunGameplay()

osu.Game.Tests/Visual/Multiplayer/TestSceneDrawableLoungeRoom.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Linq;
 using System.Threading;
@@ -10,6 +8,7 @@ using System.Threading.Tasks;
 using Moq;
 using NUnit.Framework;
 using osu.Framework.Allocation;
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Cursor;
 using osu.Framework.Testing;
@@ -25,14 +24,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
     {
         private readonly Room room = new Room
         {
-            HasPassword = { Value = true }
+            Password = "*"
         };
 
         [Cached]
         protected readonly OverlayColourProvider ColourProvider = new OverlayColourProvider(OverlayColourScheme.Pink);
 
-        private DrawableLoungeRoom drawableRoom;
-        private SearchTextBox searchTextBox;
+        private DrawableLoungeRoom drawableRoom = null!;
+        private SearchTextBox searchTextBox = null!;
 
         private readonly ManualResetEventSlim allowResponseCallback = new ManualResetEventSlim();
 
@@ -78,6 +77,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                         {
                             Anchor = Anchor.Centre,
                             Origin = Anchor.Centre,
+                            SelectedRoom = new Bindable<Room?>()
                         }
                     }
                 };
@@ -87,7 +87,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         [Test]
         public void TestFocusViaKeyboardCommit()
         {
-            DrawableLoungeRoom.PasswordEntryPopover popover = null;
+            DrawableLoungeRoom.PasswordEntryPopover? popover = null;
 
             AddAssert("search textbox has focus", () => checkFocus(searchTextBox));
             AddStep("click room twice", () =>
@@ -103,11 +103,11 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddStep("enter password", () => popover.ChildrenOfType<OsuPasswordTextBox>().Single().Text = "password");
             AddStep("commit via enter", () => InputManager.Key(Key.Enter));
 
-            AddAssert("popover has focus", () => checkFocus(popover));
+            AddAssert("popover has focus", () => checkFocus(popover!));
 
             AddStep("attempt another enter", () => InputManager.Key(Key.Enter));
 
-            AddAssert("popover still has focus", () => checkFocus(popover));
+            AddAssert("popover still has focus", () => checkFocus(popover!));
 
             AddStep("unblock response", () => allowResponseCallback.Set());
 
@@ -122,7 +122,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         [Test]
         public void TestFocusViaMouseCommit()
         {
-            DrawableLoungeRoom.PasswordEntryPopover popover = null;
+            DrawableLoungeRoom.PasswordEntryPopover? popover = null;
 
             AddAssert("search textbox has focus", () => checkFocus(searchTextBox));
             AddStep("click room twice", () =>
@@ -144,11 +144,11 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 InputManager.Click(MouseButton.Left);
             });
 
-            AddAssert("popover has focus", () => checkFocus(popover));
+            AddAssert("popover has focus", () => checkFocus(popover!));
 
             AddStep("attempt another click", () => InputManager.Click(MouseButton.Left));
 
-            AddAssert("popover still has focus", () => checkFocus(popover));
+            AddAssert("popover still has focus", () => checkFocus(popover!));
 
             AddStep("unblock response", () => allowResponseCallback.Set());
 

osu.Game.Tests/Visual/Multiplayer/TestSceneDrawableRoom.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Linq;
 using NUnit.Framework;
@@ -32,15 +30,40 @@ namespace osu.Game.Tests.Visual.Multiplayer
         [Cached]
         protected readonly OverlayColourProvider ColourProvider = new OverlayColourProvider(OverlayColourScheme.Plum);
 
-        private readonly Bindable<Room> selectedRoom = new Bindable<Room>();
+        private readonly Bindable<Room?> selectedRoom = new Bindable<Room?>();
 
         [Test]
         public void TestMultipleStatuses()
         {
-            FillFlowContainer rooms = null;
+            FillFlowContainer rooms = null!;
 
             AddStep("create rooms", () =>
             {
+                PlaylistItem item1 = new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo)
+                {
+                    BeatmapInfo = { StarRating = 2.5 }
+                }.BeatmapInfo);
+
+                PlaylistItem item2 = new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo)
+                {
+                    BeatmapInfo = { StarRating = 4.5 }
+                }.BeatmapInfo);
+
+                PlaylistItem item3 = new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo)
+                {
+                    BeatmapInfo =
+                    {
+                        StarRating = 2.5,
+                        Metadata =
+                        {
+                            Artist = "very very very very very very very very very long artist",
+                            ArtistUnicode = "very very very very very very very very very long artist",
+                            Title = "very very very very very very very very very very very long title",
+                            TitleUnicode = "very very very very very very very very very very very long title",
+                        }
+                    }
+                }.BeatmapInfo);
+
                 Child = rooms = new FillFlowContainer
                 {
                     Anchor = Anchor.Centre,
@@ -52,86 +75,48 @@ namespace osu.Game.Tests.Visual.Multiplayer
                     {
                         createLoungeRoom(new Room
                         {
-                            Name = { Value = "Multiplayer room" },
-                            Status = { Value = new RoomStatusOpen() },
-                            EndDate = { Value = DateTimeOffset.Now.AddDays(1) },
-                            Type = { Value = MatchType.HeadToHead },
-                            Playlist =
-                            {
-                                new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo)
-                                {
-                                    BeatmapInfo =
-                                    {
-                                        StarRating = 2.5
-                                    }
-                                }.BeatmapInfo)
-                            }
+                            Name = "Multiplayer room",
+                            Status = new RoomStatusOpen(),
+                            EndDate = DateTimeOffset.Now.AddDays(1),
+                            Type = MatchType.HeadToHead,
+                            Playlist = [item1],
+                            CurrentPlaylistItem = item1
                         }),
                         createLoungeRoom(new Room
                         {
-                            Name = { Value = "Private room" },
-                            Status = { Value = new RoomStatusOpenPrivate() },
-                            HasPassword = { Value = true },
-                            EndDate = { Value = DateTimeOffset.Now.AddDays(1) },
-                            Type = { Value = MatchType.HeadToHead },
-                            Playlist =
-                            {
-                                new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo)
-                                {
-                                    BeatmapInfo =
-                                    {
-                                        StarRating = 2.5,
-                                        Metadata =
-                                        {
-                                            Artist = "very very very very very very very very very long artist",
-                                            ArtistUnicode = "very very very very very very very very very long artist",
-                                            Title = "very very very very very very very very very very very long title",
-                                            TitleUnicode = "very very very very very very very very very very very long title",
-                                        }
-                                    }
-                                }.BeatmapInfo)
-                            }
+                            Name = "Private room",
+                            Status = new RoomStatusOpenPrivate(),
+                            Password = "*",
+                            EndDate = DateTimeOffset.Now.AddDays(1),
+                            Type = MatchType.HeadToHead,
+                            Playlist = [item3],
+                            CurrentPlaylistItem = item3
                         }),
                         createLoungeRoom(new Room
                         {
-                            Name = { Value = "Playlist room with multiple beatmaps" },
-                            Status = { Value = new RoomStatusPlaying() },
-                            EndDate = { Value = DateTimeOffset.Now.AddDays(1) },
-                            Playlist =
-                            {
-                                new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo)
-                                {
-                                    BeatmapInfo =
-                                    {
-                                        StarRating = 2.5
-                                    }
-                                }.BeatmapInfo),
-                                new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo)
-                                {
-                                    BeatmapInfo =
-                                    {
-                                        StarRating = 4.5
-                                    }
-                                }.BeatmapInfo)
-                            }
+                            Name = "Playlist room with multiple beatmaps",
+                            Status = new RoomStatusPlaying(),
+                            EndDate = DateTimeOffset.Now.AddDays(1),
+                            Playlist = [item1, item2],
+                            CurrentPlaylistItem = item1
                         }),
                         createLoungeRoom(new Room
                         {
-                            Name = { Value = "Finished room" },
-                            Status = { Value = new RoomStatusEnded() },
-                            EndDate = { Value = DateTimeOffset.Now },
+                            Name = "Finished room",
+                            Status = new RoomStatusEnded(),
+                            EndDate = DateTimeOffset.Now,
                         }),
                         createLoungeRoom(new Room
                         {
-                            Name = { Value = "Spotlight room" },
-                            Status = { Value = new RoomStatusOpen() },
-                            Category = { Value = RoomCategory.Spotlight },
+                            Name = "Spotlight room",
+                            Status = new RoomStatusOpen(),
+                            Category = RoomCategory.Spotlight,
                         }),
                         createLoungeRoom(new Room
                         {
-                            Name = { Value = "Featured artist room" },
-                            Status = { Value = new RoomStatusOpen() },
-                            Category = { Value = RoomCategory.FeaturedArtist },
+                            Name = "Featured artist room",
+                            Status = new RoomStatusOpen(),
+                            Category = RoomCategory.FeaturedArtist,
                         }),
                     }
                 };
@@ -145,24 +130,24 @@ namespace osu.Game.Tests.Visual.Multiplayer
         [Test]
         public void TestEnableAndDisablePassword()
         {
-            DrawableRoom drawableRoom = null;
-            Room room = null;
+            DrawableRoom drawableRoom = null!;
+            Room room = null!;
 
             AddStep("create room", () => Child = drawableRoom = createLoungeRoom(room = new Room
             {
-                Name = { Value = "Room with password" },
-                Status = { Value = new RoomStatusOpen() },
-                Type = { Value = MatchType.HeadToHead },
+                Name = "Room with password",
+                Status = new RoomStatusOpen(),
+                Type = MatchType.HeadToHead,
             }));
 
             AddUntilStep("wait for panel load", () => drawableRoom.ChildrenOfType<DrawableRoomParticipantsList>().Any());
 
             AddAssert("password icon hidden", () => Precision.AlmostEquals(0, drawableRoom.ChildrenOfType<DrawableRoom.PasswordProtectedIcon>().Single().Alpha));
 
-            AddStep("set password", () => room.Password.Value = "password");
+            AddStep("set password", () => room.Password = "password");
             AddAssert("password icon visible", () => Precision.AlmostEquals(1, drawableRoom.ChildrenOfType<DrawableRoom.PasswordProtectedIcon>().Single().Alpha));
 
-            AddStep("unset password", () => room.Password.Value = string.Empty);
+            AddStep("unset password", () => room.Password = string.Empty);
             AddAssert("password icon hidden", () => Precision.AlmostEquals(0, drawableRoom.ChildrenOfType<DrawableRoom.PasswordProtectedIcon>().Single().Alpha));
         }
 
@@ -179,43 +164,52 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 {
                     new DrawableMatchRoom(new Room
                     {
-                        Name = { Value = "A host-only room" },
-                        QueueMode = { Value = QueueMode.HostOnly },
-                        Type = { Value = MatchType.HeadToHead }
-                    }),
+                        Name = "A host-only room",
+                        QueueMode = QueueMode.HostOnly,
+                        Type = MatchType.HeadToHead,
+                    })
+                    {
+                        SelectedItem = new Bindable<PlaylistItem?>()
+                    },
                     new DrawableMatchRoom(new Room
                     {
-                        Name = { Value = "An all-players, team-versus room" },
-                        QueueMode = { Value = QueueMode.AllPlayers },
-                        Type = { Value = MatchType.TeamVersus }
-                    }),
+                        Name = "An all-players, team-versus room",
+                        QueueMode = QueueMode.AllPlayers,
+                        Type = MatchType.TeamVersus
+                    })
+                    {
+                        SelectedItem = new Bindable<PlaylistItem?>()
+                    },
                     new DrawableMatchRoom(new Room
                     {
-                        Name = { Value = "A round-robin room" },
-                        QueueMode = { Value = QueueMode.AllPlayersRoundRobin },
-                        Type = { Value = MatchType.HeadToHead }
-                    }),
+                        Name = "A round-robin room",
+                        QueueMode = QueueMode.AllPlayersRoundRobin,
+                        Type = MatchType.HeadToHead
+                    })
+                    {
+                        SelectedItem = new Bindable<PlaylistItem?>()
+                    },
                 }
             });
         }
 
         private DrawableRoom createLoungeRoom(Room room)
         {
-            room.Host.Value ??= new APIUser { Username = "peppy", Id = 2 };
+            room.Host ??= new APIUser { Username = "peppy", Id = 2 };
 
             if (room.RecentParticipants.Count == 0)
             {
-                room.RecentParticipants.AddRange(Enumerable.Range(0, 20).Select(i => new APIUser
+                room.RecentParticipants = Enumerable.Range(0, 20).Select(i => new APIUser
                 {
                     Id = i,
                     Username = $"User {i}"
-                }));
+                }).ToArray();
             }
 
             return new DrawableLoungeRoom(room)
             {
                 MatchingFilter = true,
-                SelectedRoom = { BindTarget = selectedRoom }
+                SelectedRoom = selectedRoom
             };
         }
     }

osu.Game.Tests/Visual/Multiplayer/TestSceneDrawableRoomParticipantsList.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Graphics;
@@ -17,7 +15,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
 {
     public partial class TestSceneDrawableRoomParticipantsList : OnlinePlayTestScene
     {
-        private DrawableRoomParticipantsList list;
+        private DrawableRoomParticipantsList list = null!;
 
         public override void SetUpSteps()
         {
@@ -27,18 +25,15 @@ namespace osu.Game.Tests.Visual.Multiplayer
             {
                 SelectedRoom.Value = new Room
                 {
-                    Name = { Value = "test room" },
-                    Host =
+                    Name = "test room",
+                    Host = new APIUser
                     {
-                        Value = new APIUser
-                        {
-                            Id = 2,
-                            Username = "peppy",
-                        }
+                        Id = 2,
+                        Username = "peppy",
                     }
                 };
 
-                Child = list = new DrawableRoomParticipantsList
+                Child = list = new DrawableRoomParticipantsList(SelectedRoom.Value)
                 {
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
@@ -143,18 +138,18 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
         private void addUser(int id)
         {
-            SelectedRoom.Value.RecentParticipants.Add(new APIUser
+            SelectedRoom.Value.RecentParticipants = SelectedRoom.Value.RecentParticipants.Append(new APIUser
             {
                 Id = id,
                 Username = $"User {id}"
-            });
-            SelectedRoom.Value.ParticipantCount.Value++;
+            }).ToArray();
+            SelectedRoom.Value.ParticipantCount++;
         }
 
         private void removeUserAt(int index)
         {
-            SelectedRoom.Value.RecentParticipants.RemoveAt(index);
-            SelectedRoom.Value.ParticipantCount.Value--;
+            SelectedRoom.Value.RecentParticipants = SelectedRoom.Value.RecentParticipants.Where(u => !u.Equals(SelectedRoom.Value.RecentParticipants[index])).ToArray();
+            SelectedRoom.Value.ParticipantCount--;
         }
     }
 }

osu.Game.Tests/Visual/Multiplayer/TestSceneHostOnlyQueueMode.cs

@@ -46,7 +46,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 QueueMode = QueueMode.AllPlayers
             }).WaitSafely());
 
-            AddUntilStep("api room updated", () => MultiplayerClient.ClientAPIRoom?.QueueMode.Value == QueueMode.AllPlayers);
+            AddUntilStep("api room updated", () => MultiplayerClient.ClientAPIRoom?.QueueMode == QueueMode.AllPlayers);
         }
 
         [Test]

osu.Game.Tests/Visual/Multiplayer/TestSceneLoungeRoomsContainer.cs

@@ -55,20 +55,20 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddAssert("has 5 rooms", () => container.Rooms.Count == 5);
 
             AddAssert("all spotlights at top", () => container.Rooms
-                                                              .SkipWhile(r => r.Room.Category.Value == RoomCategory.Spotlight)
-                                                              .All(r => r.Room.Category.Value == RoomCategory.Normal));
+                                                              .SkipWhile(r => r.Room.Category == RoomCategory.Spotlight)
+                                                              .All(r => r.Room.Category == RoomCategory.Normal));
 
-            AddStep("remove first room", () => RoomManager.RemoveRoom(RoomManager.Rooms.First(r => r.RoomID.Value == 0)));
+            AddStep("remove first room", () => RoomManager.RemoveRoom(RoomManager.Rooms.First(r => r.RoomID == 0)));
             AddAssert("has 4 rooms", () => container.Rooms.Count == 4);
-            AddAssert("first room removed", () => container.Rooms.All(r => r.Room.RoomID.Value != 0));
+            AddAssert("first room removed", () => container.Rooms.All(r => r.Room.RoomID != 0));
 
             AddStep("select first room", () => container.Rooms.First().TriggerClick());
-            AddAssert("first spotlight selected", () => checkRoomSelected(RoomManager.Rooms.First(r => r.Category.Value == RoomCategory.Spotlight)));
+            AddAssert("first spotlight selected", () => checkRoomSelected(RoomManager.Rooms.First(r => r.Category == RoomCategory.Spotlight)));
 
-            AddStep("remove last room", () => RoomManager.RemoveRoom(RoomManager.Rooms.MinBy(r => r.RoomID?.Value)));
-            AddAssert("first spotlight still selected", () => checkRoomSelected(RoomManager.Rooms.First(r => r.Category.Value == RoomCategory.Spotlight)));
+            AddStep("remove last room", () => RoomManager.RemoveRoom(RoomManager.Rooms.MinBy(r => r.RoomID)));
+            AddAssert("first spotlight still selected", () => checkRoomSelected(RoomManager.Rooms.First(r => r.Category == RoomCategory.Spotlight)));
 
-            AddStep("remove spotlight room", () => RoomManager.RemoveRoom(RoomManager.Rooms.Single(r => r.Category.Value == RoomCategory.Spotlight)));
+            AddStep("remove spotlight room", () => RoomManager.RemoveRoom(RoomManager.Rooms.Single(r => r.Category == RoomCategory.Spotlight)));
             AddAssert("selection vacated", () => checkRoomSelected(null));
         }
 
@@ -182,11 +182,11 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
             AddStep("filter public rooms", () => container.Filter.Value = new FilterCriteria { Permissions = RoomPermissionsFilter.Public });
 
-            AddUntilStep("private room hidden", () => container.Rooms.All(r => !r.Room.HasPassword.Value));
+            AddUntilStep("private room hidden", () => container.Rooms.All(r => !r.Room.HasPassword));
 
             AddStep("filter private rooms", () => container.Filter.Value = new FilterCriteria { Permissions = RoomPermissionsFilter.Private });
 
-            AddUntilStep("public room hidden", () => container.Rooms.All(r => r.Room.HasPassword.Value));
+            AddUntilStep("public room hidden", () => container.Rooms.All(r => r.Room.HasPassword));
         }
 
         [Test]

osu.Game.Tests/Visual/Multiplayer/TestSceneMatchBeatmapDetailArea.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.Linq;
 using osu.Framework.Graphics;
 using osu.Game.Online.API;
 using osu.Game.Online.Rooms;
@@ -23,7 +24,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
             {
                 SelectedRoom.Value = new Room();
 
-                Child = new MatchBeatmapDetailArea
+                Child = new MatchBeatmapDetailArea(SelectedRoom.Value)
                 {
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
@@ -35,7 +36,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
         private void createNewItem()
         {
-            SelectedRoom.Value.Playlist.Add(new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
+            SelectedRoom.Value.Playlist = SelectedRoom.Value.Playlist.Append(new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
             {
                 ID = SelectedRoom.Value.Playlist.Count,
                 RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
@@ -45,7 +46,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                     new APIMod(new OsuModDoubleTime()),
                     new APIMod(new OsuModAutoplay())
                 }
-            });
+            }).ToArray();
         }
     }
 }

osu.Game.Tests/Visual/Multiplayer/TestSceneMatchLeaderboard.cs

@@ -61,9 +61,9 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
             AddStep("create leaderboard", () =>
             {
-                SelectedRoom.Value = new Room { RoomID = { Value = 3 } };
+                SelectedRoom.Value = new Room { RoomID = 3 };
 
-                Child = new MatchLeaderboard
+                Child = new MatchLeaderboard(SelectedRoom.Value)
                 {
                     Origin = Anchor.Centre,
                     Anchor = Anchor.Centre,

osu.Game.Tests/Visual/Multiplayer/TestSceneMatchStartControl.cs

@@ -43,12 +43,6 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
         private OsuButton readyButton => control.ChildrenOfType<OsuButton>().Single();
 
-        [Cached(typeof(IBindable<PlaylistItem>))]
-        private readonly Bindable<PlaylistItem> currentItem = new Bindable<PlaylistItem>();
-
-        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent) =>
-            new CachedModelDependencyContainer<Room>(base.CreateChildDependencies(parent)) { Model = { BindTarget = room } };
-
         [BackgroundDependencyLoader]
         private void load()
         {
@@ -107,31 +101,33 @@ namespace osu.Game.Tests.Visual.Multiplayer
         [SetUpSteps]
         public void SetUpSteps()
         {
+            PlaylistItem item = null!;
+
             AddStep("reset state", () =>
             {
                 multiplayerClient.Invocations.Clear();
 
                 beatmapAvailability.Value = BeatmapAvailability.LocallyAvailable();
 
-                currentItem.Value = new PlaylistItem(Beatmap.Value.BeatmapInfo)
+                item = new PlaylistItem(Beatmap.Value.BeatmapInfo)
                 {
                     RulesetID = Beatmap.Value.BeatmapInfo.Ruleset.OnlineID
                 };
 
                 room.Value = new Room
                 {
-                    Playlist = { currentItem.Value },
-                    CurrentPlaylistItem = { BindTarget = currentItem }
+                    Playlist = [item],
+                    CurrentPlaylistItem = item
                 };
 
-                localUser = new MultiplayerRoomUser(API.LocalUser.Value.Id) { User = API.LocalUser.Value };
+                localUser = new MultiplayerRoomUser(API.LocalUser.Value.Id)
+                {
+                    User = API.LocalUser.Value
+                };
 
                 multiplayerRoom = new MultiplayerRoom(0)
                 {
-                    Playlist =
-                    {
-                        TestMultiplayerClient.CreateMultiplayerPlaylistItem(currentItem.Value),
-                    },
+                    Playlist = { TestMultiplayerClient.CreateMultiplayerPlaylistItem(item) },
                     Users = { localUser },
                     Host = localUser,
                 };
@@ -144,6 +140,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
                     Size = new Vector2(250, 50),
+                    SelectedItem = new Bindable<PlaylistItem?>(item)
                 };
             });
         }

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayer.cs

@@ -103,14 +103,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
+                Name = "Test Room",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                }
+                ]
             });
 
             AddRepeatStep("random stuff happens", performRandomAction, 30);
@@ -238,17 +238,17 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
+                Name = "Test Room",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                }
+                ]
             });
 
-            AddUntilStep("Check participant count correct", () => multiplayerClient.ClientAPIRoom?.ParticipantCount.Value == 1);
+            AddUntilStep("Check participant count correct", () => multiplayerClient.ClientAPIRoom?.ParticipantCount == 1);
             AddUntilStep("Check participant list contains user", () => multiplayerClient.ClientAPIRoom?.RecentParticipants.Count(u => u.Id == API.LocalUser.Value.Id) == 1);
         }
 
@@ -259,14 +259,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
             {
                 roomManager.AddServerSideRoom(new Room
                 {
-                    Name = { Value = "Test Room" },
+                    Name = "Test Room",
                     Playlist =
-                    {
+                    [
                         new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                         {
                             RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                         }
-                    }
+                    ]
                 }, API.LocalUser.Value);
             });
 
@@ -288,14 +288,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
             {
                 roomManager.AddServerSideRoom(new Room
                 {
-                    Name = { Value = "Test Room" },
+                    Name = "Test Room",
                     Playlist =
-                    {
+                    [
                         new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                         {
                             RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                         }
-                    }
+                    ]
                 }, API.LocalUser.Value);
             });
 
@@ -308,7 +308,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddUntilStep("wait for room open", () => this.ChildrenOfType<MultiplayerMatchSubScreen>().FirstOrDefault()?.IsLoaded == true);
             AddUntilStep("wait for join", () => multiplayerClient.RoomJoined);
 
-            AddUntilStep("Check participant count correct", () => multiplayerClient.ClientAPIRoom?.ParticipantCount.Value == 1);
+            AddUntilStep("Check participant count correct", () => multiplayerClient.ClientAPIRoom?.ParticipantCount == 1);
             AddUntilStep("Check participant list contains user", () => multiplayerClient.ClientAPIRoom?.RecentParticipants.Count(u => u.Id == API.LocalUser.Value.Id) == 1);
         }
 
@@ -317,18 +317,18 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
-                Password = { Value = "password" },
+                Name = "Test Room",
+                Password = "password",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                }
+                ]
             });
 
-            AddUntilStep("room has password", () => multiplayerClient.ClientAPIRoom?.Password.Value == "password");
+            AddUntilStep("room has password", () => multiplayerClient.ClientAPIRoom?.Password == "password");
         }
 
         [Test]
@@ -338,15 +338,15 @@ namespace osu.Game.Tests.Visual.Multiplayer
             {
                 roomManager.AddServerSideRoom(new Room
                 {
-                    Name = { Value = "Test Room" },
-                    Password = { Value = "password" },
+                    Name = "Test Room",
+                    Password = "password",
                     Playlist =
-                    {
+                    [
                         new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                         {
                             RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                         }
-                    }
+                    ]
                 }, API.LocalUser.Value);
             });
 
@@ -370,19 +370,19 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
-                Password = { Value = "password" },
+                Name = "Test Room",
+                Password = "password",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                }
+                ]
             });
 
             AddStep("change password", () => multiplayerClient.ChangeSettings(password: "password2"));
-            AddUntilStep("local password changed", () => multiplayerClient.ClientAPIRoom?.Password.Value == "password2");
+            AddUntilStep("local password changed", () => multiplayerClient.ClientAPIRoom?.Password == "password2");
         }
 
         [Test]
@@ -401,14 +401,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
+                Name = "Test Room",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                }
+                ]
             });
 
             pressReadyButton();
@@ -430,8 +430,8 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 };
                 return new Room
                 {
-                    Name = { Value = "Test Room" },
-                    Playlist = { item }
+                    Name = "Test Room",
+                    Playlist = [item]
                 };
             });
 
@@ -471,8 +471,8 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 };
                 return new Room
                 {
-                    Name = { Value = "Test Room" },
-                    Playlist = { item }
+                    Name = "Test Room",
+                    Playlist = [item]
                 };
             });
 
@@ -512,8 +512,8 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 };
                 return new Room
                 {
-                    Name = { Value = "Test Room" },
-                    Playlist = { item }
+                    Name = "Test Room",
+                    Playlist = [item]
                 };
             });
 
@@ -548,14 +548,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
+                Name = "Test Room",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                }
+                ]
             });
 
             AddStep("join other user (ready, host)", () =>
@@ -581,14 +581,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
+                Name = "Test Room",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                }
+                ]
             });
 
             AddStep("delete beatmap", () => beatmaps.Delete(importedSet));
@@ -620,14 +620,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
+                Name = "Test Room",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                }
+                ]
             });
 
             AddStep("disconnect", () => multiplayerClient.Disconnect());
@@ -639,15 +639,15 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
+                Name = "Test Room",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
                         AllowedMods = new[] { new APIMod(new OsuModHidden()) }
                     }
-                }
+                ]
             });
 
             AddStep("open mod overlay", () => this.ChildrenOfType<UserModSelectButton>().Single().TriggerClick());
@@ -679,14 +679,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
+                Name = "Test Room",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
                     }
-                }
+                ]
             });
 
             enterGameplay();
@@ -724,14 +724,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
+                Name = "Test Room",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
                     }
-                }
+                ]
             });
 
             enterGameplay();
@@ -754,14 +754,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
+                Name = "Test Room",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
                     }
-                }
+                ]
             });
 
             pressReadyButton();
@@ -791,15 +791,15 @@ namespace osu.Game.Tests.Visual.Multiplayer
             {
                 roomManager.AddServerSideRoom(new Room
                 {
-                    Name = { Value = "Test Room" },
-                    QueueMode = { Value = QueueMode.AllPlayers },
+                    Name = "Test Room",
+                    QueueMode = QueueMode.AllPlayers,
                     Playlist =
-                    {
+                    [
                         new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                         {
                             RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
                         }
-                    }
+                    ]
                 }, API.LocalUser.Value);
             });
 
@@ -810,12 +810,15 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddStep("disable polling", () => this.ChildrenOfType<ListingPollingComponent>().Single().TimeBetweenPolls.Value = 0);
             AddStep("change server-side settings", () =>
             {
-                roomManager.ServerSideRooms[0].Name.Value = "New name";
-                roomManager.ServerSideRooms[0].Playlist.Add(new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
-                {
-                    ID = 2,
-                    RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
-                });
+                roomManager.ServerSideRooms[0].Name = "New name";
+                roomManager.ServerSideRooms[0].Playlist =
+                [
+                    new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
+                    {
+                        ID = 2,
+                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
+                    }
+                ];
             });
 
             AddStep("join room", () => InputManager.Key(Key.Enter));
@@ -825,8 +828,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddAssert("local room has correct settings", () =>
             {
                 var localRoom = this.ChildrenOfType<MultiplayerMatchSubScreen>().Single().Room;
-                return localRoom.Name.Value == roomManager.ServerSideRooms[0].Name.Value
-                       && localRoom.Playlist.SequenceEqual(roomManager.ServerSideRooms[0].Playlist);
+                return localRoom.Name == roomManager.ServerSideRooms[0].Name && localRoom.Playlist.Single().ID == 2;
             });
         }
 
@@ -836,15 +838,15 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
-                QueueMode = { Value = QueueMode.AllPlayers },
+                Name = "Test Room",
+                QueueMode = QueueMode.AllPlayers,
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
                     }
-                }
+                ]
             });
 
             AddStep("set spectating state", () => multiplayerClient.ChangeUserState(API.LocalUser.Value.OnlineID, MultiplayerUserState.Spectating));
@@ -872,15 +874,15 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
-                QueueMode = { Value = QueueMode.AllPlayers },
+                Name = "Test Room",
+                QueueMode = QueueMode.AllPlayers,
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
                     }
-                }
+                ]
             });
 
             AddStep("set spectating state", () => multiplayerClient.ChangeUserState(API.LocalUser.Value.OnlineID, MultiplayerUserState.Spectating));
@@ -911,15 +913,15 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
-                QueueMode = { Value = QueueMode.AllPlayers },
+                Name = "Test Room",
+                QueueMode = QueueMode.AllPlayers,
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
                     }
-                }
+                ]
             });
 
             enterGameplay();
@@ -942,15 +944,15 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
-                QueueMode = { Value = QueueMode.AllPlayers },
+                Name = "Test Room",
+                QueueMode = QueueMode.AllPlayers,
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
                     }
-                }
+                ]
             });
 
             enterGameplay();
@@ -976,14 +978,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
+                Name = "Test Room",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                }
+                ]
             });
 
             AddStep("join other user and make host", () =>
@@ -1022,10 +1024,10 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
-                QueueMode = { Value = QueueMode.AllPlayers },
+                Name = "Test Room",
+                QueueMode = QueueMode.AllPlayers,
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
@@ -1036,7 +1038,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                         RulesetID = new TaikoRuleset().RulesetInfo.OnlineID,
                         AllowedMods = new[] { new APIMod { Acronym = "HD" } },
                     },
-                }
+                ]
             });
 
             AddStep("select hidden", () => multiplayerClient.ChangeUserMods(new[] { new APIMod { Acronym = "HD" } }));

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerMatchFooter.cs

@@ -1,7 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -13,9 +12,6 @@ namespace osu.Game.Tests.Visual.Multiplayer
 {
     public partial class TestSceneMultiplayerMatchFooter : MultiplayerTestScene
     {
-        [Cached(typeof(IBindable<PlaylistItem>))]
-        private readonly Bindable<PlaylistItem> currentItem = new Bindable<PlaylistItem>();
-
         public override void SetUpSteps()
         {
             base.SetUpSteps();
@@ -33,7 +29,10 @@ namespace osu.Game.Tests.Visual.Multiplayer
                         Origin = Anchor.Centre,
                         RelativeSizeAxes = Axes.X,
                         Height = 50,
-                        Child = new MultiplayerMatchFooter()
+                        Child = new MultiplayerMatchFooter
+                        {
+                            SelectedItem = new Bindable<PlaylistItem?>()
+                        }
                     }
                 };
             });

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerMatchSubScreen.cs

@@ -69,7 +69,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             AddStep("load match", () =>
             {
-                SelectedRoom.Value = new Room { Name = { Value = "Test Room" } };
+                SelectedRoom.Value = new Room { Name = "Test Room" };
                 LoadScreen(screen = new TestMultiplayerMatchSubScreen(SelectedRoom.Value));
             });
 
@@ -77,33 +77,17 @@ namespace osu.Game.Tests.Visual.Multiplayer
         }
 
         [Test]
-        [FlakyTest]
-        /*
-         * Fail rate around 1.5%
-         *
-         * TearDown : System.AggregateException : One or more errors occurred. (Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index'))
-  ----> System.ArgumentOutOfRangeException : Index was out of range. Must be non-negative and less than the size of the collection. (Parameter 'index')
-         * --TearDown
-         *    at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
-         *   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
-         *   at osu.Framework.Extensions.TaskExtensions.WaitSafely(Task task)
-         *   at osu.Framework.Testing.TestScene.checkForErrors()
-         *   at osu.Framework.Testing.TestScene.RunTestsFromNUnit()
-         *--ArgumentOutOfRangeException
-         *   at osu.Framework.Bindables.BindableList`1.removeAt(Int32 index, BindableList`1 caller)
-         *   at osu.Framework.Bindables.BindableList`1.removeAt(Int32 index, BindableList`1 caller)
-         *   at osu.Framework.Bindables.BindableList`1.removeAt(Int32 index, BindableList`1 caller)
-         *   at osu.Game.Online.Multiplayer.MultiplayerClient.<>c__DisplayClass106_0.<PlaylistItemChanged>b__0() in C:\BuildAgent\work\ecd860037212ac52\osu.Game\Online\Multiplayer\MultiplayerClient     .cs:line 702
-         *   at osu.Framework.Threading.ScheduledDelegate.RunTaskInternal()
-         */
         public void TestCreatedRoom()
         {
             AddStep("add playlist item", () =>
             {
-                SelectedRoom.Value.Playlist.Add(new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
-                {
-                    RulesetID = new OsuRuleset().RulesetInfo.OnlineID
-                });
+                SelectedRoom.Value.Playlist =
+                [
+                    new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
+                    {
+                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID
+                    }
+                ];
             });
 
             ClickButtonWhenEnabled<MultiplayerMatchSettingsOverlay.CreateOrUpdateButton>();
@@ -112,16 +96,18 @@ namespace osu.Game.Tests.Visual.Multiplayer
         }
 
         [Test]
-        [FlakyTest] // See above
         public void TestTaikoOnlyMod()
         {
             AddStep("add playlist item", () =>
             {
-                SelectedRoom.Value.Playlist.Add(new PlaylistItem(new TestBeatmap(new TaikoRuleset().RulesetInfo).BeatmapInfo)
-                {
-                    RulesetID = new TaikoRuleset().RulesetInfo.OnlineID,
-                    AllowedMods = new[] { new APIMod(new TaikoModSwap()) }
-                });
+                SelectedRoom.Value.Playlist =
+                [
+                    new PlaylistItem(new TestBeatmap(new TaikoRuleset().RulesetInfo).BeatmapInfo)
+                    {
+                        RulesetID = new TaikoRuleset().RulesetInfo.OnlineID,
+                        AllowedMods = new[] { new APIMod(new TaikoModSwap()) }
+                    }
+                ];
             });
 
             ClickButtonWhenEnabled<MultiplayerMatchSettingsOverlay.CreateOrUpdateButton>();
@@ -133,32 +119,36 @@ namespace osu.Game.Tests.Visual.Multiplayer
         }
 
         [Test]
-        [FlakyTest] // See above
         public void TestSettingValidity()
         {
             AddAssert("create button not enabled", () => !this.ChildrenOfType<MultiplayerMatchSettingsOverlay.CreateOrUpdateButton>().Single().Enabled.Value);
 
             AddStep("set playlist", () =>
             {
-                SelectedRoom.Value.Playlist.Add(new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
-                {
-                    RulesetID = new OsuRuleset().RulesetInfo.OnlineID
-                });
+                SelectedRoom.Value.Playlist =
+                [
+                    new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
+                    {
+                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID
+                    }
+                ];
             });
 
             AddAssert("create button enabled", () => this.ChildrenOfType<MultiplayerMatchSettingsOverlay.CreateOrUpdateButton>().Single().Enabled.Value);
         }
 
         [Test]
-        [FlakyTest] // See above
         public void TestStartMatchWhileSpectating()
         {
             AddStep("set playlist", () =>
             {
-                SelectedRoom.Value.Playlist.Add(new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First()).BeatmapInfo)
-                {
-                    RulesetID = new OsuRuleset().RulesetInfo.OnlineID
-                });
+                SelectedRoom.Value.Playlist =
+                [
+                    new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First()).BeatmapInfo)
+                    {
+                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID
+                    }
+                ];
             });
 
             ClickButtonWhenEnabled<MultiplayerMatchSettingsOverlay.CreateOrUpdateButton>();
@@ -179,16 +169,18 @@ namespace osu.Game.Tests.Visual.Multiplayer
         }
 
         [Test]
-        [FlakyTest] // See above
         public void TestFreeModSelectionHasAllowedMods()
         {
             AddStep("add playlist item with allowed mod", () =>
             {
-                SelectedRoom.Value.Playlist.Add(new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
-                {
-                    RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
-                    AllowedMods = new[] { new APIMod(new OsuModDoubleTime()) }
-                });
+                SelectedRoom.Value.Playlist =
+                [
+                    new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
+                    {
+                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
+                        AllowedMods = new[] { new APIMod(new OsuModDoubleTime()) }
+                    }
+                ];
             });
 
             ClickButtonWhenEnabled<MultiplayerMatchSettingsOverlay.CreateOrUpdateButton>();
@@ -206,16 +198,18 @@ namespace osu.Game.Tests.Visual.Multiplayer
         }
 
         [Test]
-        [FlakyTest] // See above
         public void TestModSelectKeyWithAllowedMods()
         {
             AddStep("add playlist item with allowed mod", () =>
             {
-                SelectedRoom.Value.Playlist.Add(new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
-                {
-                    RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
-                    AllowedMods = new[] { new APIMod(new OsuModDoubleTime()) }
-                });
+                SelectedRoom.Value.Playlist =
+                [
+                    new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
+                    {
+                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
+                        AllowedMods = new[] { new APIMod(new OsuModDoubleTime()) }
+                    }
+                ];
             });
 
             ClickButtonWhenEnabled<MultiplayerMatchSettingsOverlay.CreateOrUpdateButton>();
@@ -228,15 +222,17 @@ namespace osu.Game.Tests.Visual.Multiplayer
         }
 
         [Test]
-        [FlakyTest] // See above
         public void TestModSelectKeyWithNoAllowedMods()
         {
             AddStep("add playlist item with no allowed mods", () =>
             {
-                SelectedRoom.Value.Playlist.Add(new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
-                {
-                    RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
-                });
+                SelectedRoom.Value.Playlist =
+                [
+                    new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
+                    {
+                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
+                    }
+                ];
             });
             ClickButtonWhenEnabled<MultiplayerMatchSettingsOverlay.CreateOrUpdateButton>();
 
@@ -249,13 +245,12 @@ namespace osu.Game.Tests.Visual.Multiplayer
         }
 
         [Test]
-        [FlakyTest] // See above
         public void TestNextPlaylistItemSelectedAfterCompletion()
         {
             AddStep("add two playlist items", () =>
             {
-                SelectedRoom.Value.Playlist.AddRange(new[]
-                {
+                SelectedRoom.Value.Playlist =
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First()).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
@@ -264,7 +259,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                });
+                ];
             });
 
             ClickButtonWhenEnabled<MultiplayerMatchSettingsOverlay.CreateOrUpdateButton>();
@@ -286,24 +281,26 @@ namespace osu.Game.Tests.Visual.Multiplayer
         }
 
         [Test]
-        [FlakyTest] // See above
         public void TestModSelectOverlay()
         {
             AddStep("add playlist item", () =>
             {
-                SelectedRoom.Value.Playlist.Add(new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
-                {
-                    RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
-                    RequiredMods = new[]
+                SelectedRoom.Value.Playlist =
+                [
+                    new PlaylistItem(new TestBeatmap(new OsuRuleset().RulesetInfo).BeatmapInfo)
                     {
-                        new APIMod(new OsuModDoubleTime { SpeedChange = { Value = 2.0 } }),
-                        new APIMod(new OsuModStrictTracking()),
-                    },
-                    AllowedMods = new[]
-                    {
-                        new APIMod(new OsuModFlashlight()),
+                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
+                        RequiredMods = new[]
+                        {
+                            new APIMod(new OsuModDoubleTime { SpeedChange = { Value = 2.0 } }),
+                            new APIMod(new OsuModStrictTracking()),
+                        },
+                        AllowedMods = new[]
+                        {
+                            new APIMod(new OsuModFlashlight()),
+                        }
                     }
-                });
+                ];
             });
             ClickButtonWhenEnabled<MultiplayerMatchSettingsOverlay.CreateOrUpdateButton>();
 

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerPlayer.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.Linq;
@@ -22,7 +20,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
 {
     public partial class TestSceneMultiplayerPlayer : MultiplayerTestScene
     {
-        private MultiplayerPlayer player;
+        private MultiplayerPlayer player = null!;
 
         [Test]
         public void TestGameplay()
@@ -49,7 +47,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddUntilStep("score changed", () => player.GameplayState.ScoreProcessor.TotalScore.Value > 0);
         }
 
-        private void setup(Func<IReadOnlyList<Mod>> mods = null)
+        private void setup(Func<IReadOnlyList<Mod>>? mods = null)
         {
             AddStep("set beatmap", () =>
             {
@@ -64,10 +62,10 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
             AddStep("initialise gameplay", () =>
             {
-                Stack.Push(player = new MultiplayerPlayer(MultiplayerClient.ServerAPIRoom, new PlaylistItem(Beatmap.Value.BeatmapInfo)
+                Stack.Push(player = new MultiplayerPlayer(MultiplayerClient.ServerAPIRoom!, new PlaylistItem(Beatmap.Value.BeatmapInfo)
                 {
                     RulesetID = Beatmap.Value.BeatmapInfo.Ruleset.OnlineID,
-                }, MultiplayerClient.ServerRoom?.Users.ToArray()));
+                }, MultiplayerClient.ServerRoom!.Users.ToArray()));
             });
 
             AddUntilStep("wait for player to be current", () => player.IsCurrentScreen() && player.IsLoaded);

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerPlaylist.cs

@@ -28,9 +28,6 @@ namespace osu.Game.Tests.Visual.Multiplayer
 {
     public partial class TestSceneMultiplayerPlaylist : MultiplayerTestScene
     {
-        [Cached(typeof(IBindable<PlaylistItem>))]
-        private readonly Bindable<PlaylistItem> currentItem = new Bindable<PlaylistItem>();
-
         private MultiplayerPlaylist list = null!;
         private BeatmapManager beatmaps = null!;
         private BeatmapSetInfo importedSet = null!;
@@ -51,12 +48,13 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
             AddStep("create list", () =>
             {
-                Child = list = new MultiplayerPlaylist
+                Child = list = new MultiplayerPlaylist(SelectedRoom.Value)
                 {
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
                     RelativeSizeAxes = Axes.Both,
-                    Size = new Vector2(0.4f, 0.8f)
+                    Size = new Vector2(0.4f, 0.8f),
+                    SelectedItem = new Bindable<PlaylistItem?>()
                 };
             });
 
@@ -166,9 +164,9 @@ namespace osu.Game.Tests.Visual.Multiplayer
             {
                 RoomManager.CreateRoom(new Room
                 {
-                    Name = { Value = "test name" },
+                    Name = "test name",
                     Playlist =
-                    {
+                    [
                         new PlaylistItem(new TestBeatmap(Ruleset.Value).BeatmapInfo)
                         {
                             RulesetID = Ruleset.Value.OnlineID
@@ -178,7 +176,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                             RulesetID = Ruleset.Value.OnlineID,
                             Expired = true
                         }
-                    }
+                    ]
                 });
             });
 

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerQueueList.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Linq;
 using NUnit.Framework;
@@ -27,10 +25,10 @@ namespace osu.Game.Tests.Visual.Multiplayer
 {
     public partial class TestSceneMultiplayerQueueList : MultiplayerTestScene
     {
-        private MultiplayerQueueList playlist;
-        private BeatmapManager beatmaps;
-        private BeatmapSetInfo importedSet;
-        private BeatmapInfo importedBeatmap;
+        private MultiplayerQueueList playlist = null!;
+        private BeatmapManager beatmaps = null!;
+        private BeatmapSetInfo importedSet = null!;
+        private BeatmapInfo importedBeatmap = null!;
 
         [BackgroundDependencyLoader]
         private void load(GameHost host, AudioManager audio)
@@ -46,12 +44,17 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
             AddStep("create playlist", () =>
             {
-                Child = playlist = new MultiplayerQueueList
+                Child = playlist = new MultiplayerQueueList(SelectedRoom.Value)
                 {
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
                     Size = new Vector2(500, 300),
-                    Items = { BindTarget = MultiplayerClient.ClientAPIRoom!.Playlist }
+                };
+
+                MultiplayerClient.ClientAPIRoom!.PropertyChanged += (_, e) =>
+                {
+                    if (e.PropertyName == nameof(Room.Playlist))
+                        playlist.Items.ReplaceRange(0, playlist.Items.Count, MultiplayerClient.ClientAPIRoom.Playlist);
                 };
             });
 
@@ -69,7 +72,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         public void TestDeleteButtonAlwaysVisibleForHost()
         {
             AddStep("set all players queue mode", () => MultiplayerClient.ChangeSettings(new MultiplayerRoomSettings { QueueMode = QueueMode.AllPlayers }).WaitSafely());
-            AddUntilStep("wait for queue mode change", () => MultiplayerClient.ClientAPIRoom?.QueueMode.Value == QueueMode.AllPlayers);
+            AddUntilStep("wait for queue mode change", () => MultiplayerClient.ClientAPIRoom?.QueueMode == QueueMode.AllPlayers);
 
             addPlaylistItem(() => API.LocalUser.Value.OnlineID);
             assertDeleteButtonVisibility(1, true);
@@ -81,7 +84,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         public void TestDeleteButtonOnlyVisibleForItemOwnerIfNotHost()
         {
             AddStep("set all players queue mode", () => MultiplayerClient.ChangeSettings(new MultiplayerRoomSettings { QueueMode = QueueMode.AllPlayers }).WaitSafely());
-            AddUntilStep("wait for queue mode change", () => MultiplayerClient.ClientAPIRoom?.QueueMode.Value == QueueMode.AllPlayers);
+            AddUntilStep("wait for queue mode change", () => MultiplayerClient.ClientAPIRoom?.QueueMode == QueueMode.AllPlayers);
 
             AddStep("join other user", () => MultiplayerClient.AddUser(new APIUser { Id = 1234 }));
             AddStep("set other user as host", () => MultiplayerClient.TransferHost(1234));
@@ -100,7 +103,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         public void TestSingleItemDoesNotHaveDeleteButton()
         {
             AddStep("set all players queue mode", () => MultiplayerClient.ChangeSettings(new MultiplayerRoomSettings { QueueMode = QueueMode.AllPlayers }).WaitSafely());
-            AddUntilStep("wait for queue mode change", () => MultiplayerClient.ClientAPIRoom?.QueueMode.Value == QueueMode.AllPlayers);
+            AddUntilStep("wait for queue mode change", () => MultiplayerClient.ClientAPIRoom?.QueueMode == QueueMode.AllPlayers);
 
             assertDeleteButtonVisibility(0, false);
         }
@@ -109,7 +112,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         public void TestCurrentItemHasDeleteButtonIfNotSingle()
         {
             AddStep("set all players queue mode", () => MultiplayerClient.ChangeSettings(new MultiplayerRoomSettings { QueueMode = QueueMode.AllPlayers }).WaitSafely());
-            AddUntilStep("wait for queue mode change", () => MultiplayerClient.ClientAPIRoom?.QueueMode.Value == QueueMode.AllPlayers);
+            AddUntilStep("wait for queue mode change", () => MultiplayerClient.ClientAPIRoom?.QueueMode == QueueMode.AllPlayers);
 
             addPlaylistItem(() => API.LocalUser.Value.OnlineID);
 

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerSpectateButton.cs

@@ -26,9 +26,6 @@ namespace osu.Game.Tests.Visual.Multiplayer
 {
     public partial class TestSceneMultiplayerSpectateButton : MultiplayerTestScene
     {
-        [Cached(typeof(IBindable<PlaylistItem>))]
-        private readonly Bindable<PlaylistItem> currentItem = new Bindable<PlaylistItem>();
-
         private MultiplayerSpectateButton spectateButton = null!;
         private MatchStartControl startControl = null!;
 
@@ -51,13 +48,13 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
             AddStep("create button", () =>
             {
-                AvailabilityTracker.SelectedItem.BindTo(currentItem);
+                PlaylistItem item = SelectedRoom.Value.Playlist.First();
+
+                AvailabilityTracker.SelectedItem.Value = item;
 
                 importedSet = beatmaps.GetAllUsableBeatmapSets().First();
                 Beatmap.Value = beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First());
 
-                currentItem.Value = SelectedRoom.Value.Playlist.First();
-
                 Child = new PopoverContainer
                 {
                     RelativeSizeAxes = Axes.Both,
@@ -72,12 +69,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
                                 Anchor = Anchor.Centre,
                                 Origin = Anchor.Centre,
                                 Size = new Vector2(200, 50),
+                                SelectedItem = new Bindable<PlaylistItem?>(item)
                             },
                             startControl = new MatchStartControl
                             {
                                 Anchor = Anchor.Centre,
                                 Origin = Anchor.Centre,
                                 Size = new Vector2(200, 50),
+                                SelectedItem = new Bindable<PlaylistItem?>(item)
                             }
                         }
                     }

osu.Game.Tests/Visual/Multiplayer/TestScenePlaylistsSongSelect.cs

@@ -74,14 +74,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
         [Test]
         public void TestItemAddedWhenCreateNewItemClicked()
         {
-            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem());
+            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem!());
             AddAssert("playlist has 1 item", () => SelectedRoom.Value.Playlist.Count == 1);
         }
 
         [Test]
         public void TestItemNotAddedIfExistingOnStart()
         {
-            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem());
+            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem!());
             AddStep("finalise selection", () => songSelect.FinaliseSelection());
             AddAssert("playlist has 1 item", () => SelectedRoom.Value.Playlist.Count == 1);
         }
@@ -89,24 +89,19 @@ namespace osu.Game.Tests.Visual.Multiplayer
         [Test]
         public void TestAddSameItemMultipleTimes()
         {
-            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem());
-            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem());
+            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem!());
+            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem!());
             AddAssert("playlist has 2 items", () => SelectedRoom.Value.Playlist.Count == 2);
         }
 
         [Test]
         public void TestAddItemAfterRearrangement()
         {
-            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem());
-            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem());
-            AddStep("rearrange", () =>
-            {
-                var item = SelectedRoom.Value.Playlist[0];
-                SelectedRoom.Value.Playlist.RemoveAt(0);
-                SelectedRoom.Value.Playlist.Add(item);
-            });
+            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem!());
+            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem!());
+            AddStep("rearrange", () => SelectedRoom.Value.Playlist = SelectedRoom.Value.Playlist.Skip(1).Append(SelectedRoom.Value.Playlist[0]).ToArray());
 
-            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem());
+            AddStep("create new item", () => songSelect.BeatmapDetails.CreateNewItem!());
             AddAssert("new item has id 2", () => SelectedRoom.Value.Playlist.Last().ID == 2);
         }
 
@@ -117,9 +112,9 @@ namespace osu.Game.Tests.Visual.Multiplayer
         public void TestNewItemHasNewModInstances()
         {
             AddStep("set dt mod", () => SelectedMods.Value = new[] { new OsuModDoubleTime() });
-            AddStep("create item", () => songSelect.BeatmapDetails.CreateNewItem());
+            AddStep("create item", () => songSelect.BeatmapDetails.CreateNewItem!());
             AddStep("change mod rate", () => ((OsuModDoubleTime)SelectedMods.Value[0]).SpeedChange.Value = 2);
-            AddStep("create item", () => songSelect.BeatmapDetails.CreateNewItem());
+            AddStep("create item", () => songSelect.BeatmapDetails.CreateNewItem!());
 
             AddAssert("item 1 has rate 1.5", () =>
             {
@@ -150,7 +145,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 mod = (OsuModDoubleTime)SelectedMods.Value[0];
             });
 
-            AddStep("create item", () => songSelect.BeatmapDetails.CreateNewItem());
+            AddStep("create item", () => songSelect.BeatmapDetails.CreateNewItem!());
 
             AddStep("change stored mod rate", () => mod.SpeedChange.Value = 2);
             AddAssert("item has rate 1.5", () =>

osu.Game.Tests/Visual/Multiplayer/TestSceneRankRangePill.cs

@@ -9,7 +9,6 @@ using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Online.Multiplayer;
-using osu.Game.Online.Rooms;
 using osu.Game.Screens.OnlinePlay.Lounge.Components;
 
 namespace osu.Game.Tests.Visual.Multiplayer
@@ -18,10 +17,6 @@ namespace osu.Game.Tests.Visual.Multiplayer
     {
         private readonly Mock<MultiplayerClient> multiplayerClient = new Mock<MultiplayerClient>();
 
-        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent) =>
-            // not used directly in component, but required due to it inheriting from OnlinePlayComposite.
-            new CachedModelDependencyContainer<Room>(base.CreateChildDependencies(parent));
-
         [BackgroundDependencyLoader]
         private void load()
         {

osu.Game.Tests/Visual/Multiplayer/TestSceneStarRatingRangeDisplay.cs

@@ -20,7 +20,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
             {
                 SelectedRoom.Value = new Room();
 
-                Child = new StarRatingRangeDisplay
+                Child = new StarRatingRangeDisplay(SelectedRoom.Value)
                 {
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre
@@ -33,11 +33,11 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             AddStep("set playlist", () =>
             {
-                SelectedRoom.Value.Playlist.AddRange(new[]
-                {
+                SelectedRoom.Value.Playlist =
+                [
                     new PlaylistItem(new BeatmapInfo { StarRating = min }),
                     new PlaylistItem(new BeatmapInfo { StarRating = max }),
-                });
+                ];
             });
         }
     }

osu.Game.Tests/Visual/Multiplayer/TestSceneTeamVersus.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Linq;
 using NUnit.Framework;
@@ -29,10 +27,10 @@ namespace osu.Game.Tests.Visual.Multiplayer
 {
     public partial class TestSceneTeamVersus : ScreenTestScene
     {
-        private BeatmapManager beatmaps;
-        private BeatmapSetInfo importedSet;
+        private BeatmapManager beatmaps = null!;
+        private BeatmapSetInfo importedSet = null!;
 
-        private TestMultiplayerComponents multiplayerComponents;
+        private TestMultiplayerComponents multiplayerComponents = null!;
 
         private TestMultiplayerClient multiplayerClient => multiplayerComponents.MultiplayerClient;
 
@@ -64,15 +62,15 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
-                Type = { Value = MatchType.TeamVersus },
+                Name = "Test Room",
+                Type = MatchType.TeamVersus,
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                }
+                ]
             });
 
             AddUntilStep("room type is team vs", () => multiplayerClient.ClientRoom?.Settings.MatchType == MatchType.TeamVersus);
@@ -84,15 +82,15 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
-                Type = { Value = MatchType.TeamVersus },
+                Name = "Test Room",
+                Type = MatchType.TeamVersus,
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                }
+                ]
             });
 
             AddUntilStep("user on team 0", () => (multiplayerClient.ClientRoom?.Users.FirstOrDefault()?.MatchState as TeamVersusUserState)?.TeamID == 0);
@@ -121,25 +119,25 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
-                Type = { Value = MatchType.HeadToHead },
+                Name = "Test Room",
+                Type = MatchType.HeadToHead,
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
                     }
-                }
+                ]
             });
 
-            AddUntilStep("match type head to head", () => multiplayerClient.ClientAPIRoom?.Type.Value == MatchType.HeadToHead);
+            AddUntilStep("match type head to head", () => multiplayerClient.ClientAPIRoom?.Type == MatchType.HeadToHead);
 
             AddStep("change match type", () => multiplayerClient.ChangeSettings(new MultiplayerRoomSettings
             {
                 MatchType = MatchType.TeamVersus
             }).WaitSafely());
 
-            AddUntilStep("api room updated to team versus", () => multiplayerClient.ClientAPIRoom?.Type.Value == MatchType.TeamVersus);
+            AddUntilStep("api room updated to team versus", () => multiplayerClient.ClientAPIRoom?.Type == MatchType.TeamVersus);
         }
 
         [Test]
@@ -147,14 +145,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             createRoom(() => new Room
             {
-                Name = { Value = "Test Room" },
+                Name = "Test Room",
                 Playlist =
-                {
+                [
                     new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
                     {
                         RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
                     }
-                }
+                ]
             });
 
             AddUntilStep("room type is head to head", () => multiplayerClient.ClientRoom?.Settings.MatchType == MatchType.HeadToHead);

osu.Game.Tests/Visual/Playlists/TestScenePlaylistsMatchSettingsOverlay.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using NUnit.Framework;
 using osu.Framework.Bindables;
@@ -22,7 +20,7 @@ namespace osu.Game.Tests.Visual.Playlists
     {
         protected new TestRoomManager RoomManager => (TestRoomManager)base.RoomManager;
 
-        private TestRoomSettings settings;
+        private TestRoomSettings settings = null!;
 
         protected override OnlinePlayTestSceneDependencies CreateOnlinePlayDependencies() => new TestDependencies();
 
@@ -47,19 +45,19 @@ namespace osu.Game.Tests.Visual.Playlists
         {
             AddStep("clear name and beatmap", () =>
             {
-                SelectedRoom.Value.Name.Value = "";
-                SelectedRoom.Value.Playlist.Clear();
+                SelectedRoom.Value.Name = "";
+                SelectedRoom.Value.Playlist = [];
             });
 
             AddAssert("button disabled", () => !settings.ApplyButton.Enabled.Value);
 
-            AddStep("set name", () => SelectedRoom.Value.Name.Value = "Room name");
+            AddStep("set name", () => SelectedRoom.Value.Name = "Room name");
             AddAssert("button disabled", () => !settings.ApplyButton.Enabled.Value);
 
-            AddStep("set beatmap", () => SelectedRoom.Value.Playlist.Add(new PlaylistItem(CreateBeatmap(Ruleset.Value).BeatmapInfo)));
+            AddStep("set beatmap", () => SelectedRoom.Value.Playlist = [new PlaylistItem(CreateBeatmap(Ruleset.Value).BeatmapInfo)]);
             AddAssert("button enabled", () => settings.ApplyButton.Enabled.Value);
 
-            AddStep("clear name", () => SelectedRoom.Value.Name.Value = "");
+            AddStep("clear name", () => SelectedRoom.Value.Name = "");
             AddAssert("button disabled", () => !settings.ApplyButton.Enabled.Value);
         }
 
@@ -69,13 +67,13 @@ namespace osu.Game.Tests.Visual.Playlists
             const string expected_name = "expected name";
             TimeSpan expectedDuration = TimeSpan.FromMinutes(15);
 
-            Room createdRoom = null;
+            Room createdRoom = null!;
 
             AddStep("setup", () =>
             {
                 settings.NameField.Current.Value = expected_name;
                 settings.DurationField.Current.Value = expectedDuration;
-                SelectedRoom.Value.Playlist.Add(new PlaylistItem(CreateBeatmap(Ruleset.Value).BeatmapInfo));
+                SelectedRoom.Value.Playlist = [new PlaylistItem(CreateBeatmap(Ruleset.Value).BeatmapInfo)];
 
                 RoomManager.CreateRequested = r =>
                 {
@@ -85,8 +83,8 @@ namespace osu.Game.Tests.Visual.Playlists
             });
 
             AddStep("create room", () => settings.ApplyButton.Action.Invoke());
-            AddAssert("has correct name", () => createdRoom.Name.Value == expected_name);
-            AddAssert("has correct duration", () => createdRoom.Duration.Value == expectedDuration);
+            AddAssert("has correct name", () => createdRoom.Name == expected_name);
+            AddAssert("has correct duration", () => createdRoom.Duration == expectedDuration);
         }
 
         [Test]
@@ -94,14 +92,14 @@ namespace osu.Game.Tests.Visual.Playlists
         {
             const string not_found_prefix = "beatmaps not found:";
 
-            string errorMessage = null;
+            string errorMessage = null!;
 
             AddStep("setup", () =>
             {
                 var beatmap = CreateBeatmap(Ruleset.Value).BeatmapInfo;
 
-                SelectedRoom.Value.Name.Value = "Test Room";
-                SelectedRoom.Value.Playlist.Add(new PlaylistItem(beatmap));
+                SelectedRoom.Value.Name = "Test Room";
+                SelectedRoom.Value.Playlist = [new PlaylistItem(beatmap)];
 
                 errorMessage = $"{not_found_prefix} {beatmap.OnlineID}";
 
@@ -127,8 +125,8 @@ namespace osu.Game.Tests.Visual.Playlists
 
             AddStep("setup", () =>
             {
-                SelectedRoom.Value.Name.Value = "Test Room";
-                SelectedRoom.Value.Playlist.Add(new PlaylistItem(CreateBeatmap(Ruleset.Value).BeatmapInfo));
+                SelectedRoom.Value.Name = "Test Room";
+                SelectedRoom.Value.Playlist = [new PlaylistItem(CreateBeatmap(Ruleset.Value).BeatmapInfo)];
 
                 RoomManager.CreateRequested = _ => failText;
             });
@@ -169,7 +167,7 @@ namespace osu.Game.Tests.Visual.Playlists
 
         protected class TestRoomManager : IRoomManager
         {
-            public Func<Room, string> CreateRequested;
+            public Func<Room, string>? CreateRequested;
 
             public event Action RoomsUpdated
             {
@@ -187,7 +185,7 @@ namespace osu.Game.Tests.Visual.Playlists
 
             public void ClearRooms() => throw new NotImplementedException();
 
-            public void CreateRoom(Room room, Action<Room> onSuccess = null, Action<string> onError = null)
+            public void CreateRoom(Room room, Action<Room>? onSuccess = null, Action<string>? onError = null)
             {
                 if (CreateRequested == null)
                     return;
@@ -200,7 +198,7 @@ namespace osu.Game.Tests.Visual.Playlists
                     onSuccess?.Invoke(room);
             }
 
-            public void JoinRoom(Room room, string password, Action<Room> onSuccess = null, Action<string> onError = null) => throw new NotImplementedException();
+            public void JoinRoom(Room room, string? password, Action<Room>? onSuccess = null, Action<string>? onError = null) => throw new NotImplementedException();
 
             public void PartRoom() => throw new NotImplementedException();
         }

osu.Game.Tests/Visual/Playlists/TestScenePlaylistsParticipantsList.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Graphics;
 using osu.Game.Online.API.Requests.Responses;
@@ -19,17 +20,16 @@ namespace osu.Game.Tests.Visual.Playlists
 
             AddStep("create list", () =>
             {
-                SelectedRoom.Value = new Room { RoomID = { Value = 7 } };
-
-                for (int i = 0; i < 50; i++)
+                SelectedRoom.Value = new Room
                 {
-                    SelectedRoom.Value.RecentParticipants.Add(new APIUser
+                    RoomID = 7,
+                    RecentParticipants = Enumerable.Range(0, 50).Select(_ => new APIUser
                     {
                         Username = "peppy",
                         Statistics = new UserStatistics { GlobalRank = 1234 },
                         Id = 2
-                    });
-                }
+                    }).ToArray()
+                };
             });
         }
 
@@ -38,7 +38,7 @@ namespace osu.Game.Tests.Visual.Playlists
         {
             AddStep("create component", () =>
             {
-                Child = new ParticipantsDisplay(Direction.Horizontal)
+                Child = new ParticipantsDisplay(SelectedRoom.Value, Direction.Horizontal)
                 {
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
@@ -52,7 +52,7 @@ namespace osu.Game.Tests.Visual.Playlists
         {
             AddStep("create component", () =>
             {
-                Child = new ParticipantsDisplay(Direction.Vertical)
+                Child = new ParticipantsDisplay(SelectedRoom.Value, Direction.Vertical)
                 {
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,

osu.Game.Tests/Visual/Playlists/TestScenePlaylistsRoomCreation.cs

@@ -1,12 +1,9 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Diagnostics;
 using System.Linq;
-using JetBrains.Annotations;
 using NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Audio;
@@ -35,11 +32,9 @@ namespace osu.Game.Tests.Visual.Playlists
 {
     public partial class TestScenePlaylistsRoomCreation : OnlinePlayTestScene
     {
-        private BeatmapManager manager;
-
-        private TestPlaylistsRoomSubScreen match;
-
-        private BeatmapSetInfo importedBeatmap;
+        private BeatmapManager manager = null!;
+        private TestPlaylistsRoomSubScreen match = null!;
+        private BeatmapSetInfo importedBeatmap = null!;
 
         [BackgroundDependencyLoader]
         private void load(GameHost host, AudioManager audio)
@@ -52,11 +47,11 @@ namespace osu.Game.Tests.Visual.Playlists
         [SetUpSteps]
         public void SetupSteps()
         {
-            AddStep("set room", () => SelectedRoom!.Value = new Room());
+            AddStep("set room", () => SelectedRoom.Value = new Room());
 
             importBeatmap();
 
-            AddStep("load match", () => LoadScreen(match = new TestPlaylistsRoomSubScreen(SelectedRoom!.Value)));
+            AddStep("load match", () => LoadScreen(match = new TestPlaylistsRoomSubScreen(SelectedRoom.Value)));
             AddUntilStep("wait for load", () => match.IsCurrentScreen());
         }
 
@@ -65,14 +60,17 @@ namespace osu.Game.Tests.Visual.Playlists
         {
             setupAndCreateRoom(room =>
             {
-                room.Name.Value = "my awesome room";
-                room.Host.Value = API.LocalUser.Value;
-                room.RecentParticipants.Add(room.Host.Value);
-                room.EndDate.Value = DateTimeOffset.Now.AddMinutes(5);
-                room.Playlist.Add(new PlaylistItem(importedBeatmap.Beatmaps.First())
-                {
-                    RulesetID = new OsuRuleset().RulesetInfo.OnlineID
-                });
+                room.Name = "my awesome room";
+                room.Host = API.LocalUser.Value;
+                room.RecentParticipants = [room.Host];
+                room.EndDate = DateTimeOffset.Now.AddMinutes(5);
+                room.Playlist =
+                [
+                    new PlaylistItem(importedBeatmap.Beatmaps.First())
+                    {
+                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID
+                    }
+                ];
             });
 
             AddUntilStep("Progress details are hidden", () => match.ChildrenOfType<RoomLocalUserInfo>().FirstOrDefault()?.Parent!.Alpha == 0);
@@ -88,15 +86,18 @@ namespace osu.Game.Tests.Visual.Playlists
         {
             setupAndCreateRoom(room =>
             {
-                room.Name.Value = "my awesome room";
-                room.MaxAttempts.Value = 5;
-                room.Host.Value = API.LocalUser.Value;
-                room.RecentParticipants.Add(room.Host.Value);
-                room.EndDate.Value = DateTimeOffset.Now.AddMinutes(5);
-                room.Playlist.Add(new PlaylistItem(importedBeatmap.Beatmaps.First())
-                {
-                    RulesetID = new OsuRuleset().RulesetInfo.OnlineID
-                });
+                room.Name = "my awesome room";
+                room.MaxAttempts = 5;
+                room.Host = API.LocalUser.Value;
+                room.RecentParticipants = [room.Host];
+                room.EndDate = DateTimeOffset.Now.AddMinutes(5);
+                room.Playlist =
+                [
+                    new PlaylistItem(importedBeatmap.Beatmaps.First())
+                    {
+                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID
+                    }
+                ];
             });
 
             AddUntilStep("Progress details are visible", () => match.ChildrenOfType<RoomLocalUserInfo>().FirstOrDefault()?.Parent!.Alpha == 1);
@@ -107,21 +108,24 @@ namespace osu.Game.Tests.Visual.Playlists
         {
             setupAndCreateRoom(room =>
             {
-                room.Name.Value = "my awesome room";
-                room.Host.Value = API.LocalUser.Value;
-                room.Playlist.Add(new PlaylistItem(importedBeatmap.Beatmaps.First())
-                {
-                    RulesetID = new OsuRuleset().RulesetInfo.OnlineID
-                });
+                room.Name = "my awesome room";
+                room.Host = API.LocalUser.Value;
+                room.Playlist =
+                [
+                    new PlaylistItem(importedBeatmap.Beatmaps.First())
+                    {
+                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID
+                    }
+                ];
             });
 
-            AddAssert("first playlist item selected", () => match.SelectedItem.Value == SelectedRoom!.Value.Playlist[0]);
+            AddAssert("first playlist item selected", () => match.SelectedItem.Value == SelectedRoom.Value.Playlist[0]);
         }
 
         [Test]
         public void TestBeatmapUpdatedOnReImport()
         {
-            string realHash = null;
+            string realHash = null!;
             int realOnlineId = 0;
             int realOnlineSetId = 0;
 
@@ -139,40 +143,40 @@ namespace osu.Game.Tests.Visual.Playlists
                     BeatmapInfo =
                     {
                         OnlineID = realOnlineId,
-                        Metadata = new BeatmapMetadata(),
-                        BeatmapSet =
-                        {
-                            OnlineID = realOnlineSetId
-                        }
+                        Metadata = new BeatmapMetadata()
                     },
                 };
 
+                Debug.Assert(modifiedBeatmap.BeatmapInfo.BeatmapSet != null);
+                modifiedBeatmap.BeatmapInfo.BeatmapSet!.OnlineID = realOnlineSetId;
+
                 modifiedBeatmap.HitObjects.Clear();
                 modifiedBeatmap.HitObjects.Add(new HitCircle { StartTime = 5000 });
 
-                Debug.Assert(modifiedBeatmap.BeatmapInfo.BeatmapSet != null);
-
                 manager.Import(modifiedBeatmap.BeatmapInfo.BeatmapSet);
             });
 
             // Create the room using the real beatmap values.
             setupAndCreateRoom(room =>
             {
-                room.Name.Value = "my awesome room";
-                room.Host.Value = API.LocalUser.Value;
-                room.Playlist.Add(new PlaylistItem(new BeatmapInfo
-                {
-                    MD5Hash = realHash,
-                    OnlineID = realOnlineId,
-                    Metadata = new BeatmapMetadata(),
-                    BeatmapSet = new BeatmapSetInfo
+                room.Name = "my awesome room";
+                room.Host = API.LocalUser.Value;
+                room.Playlist =
+                [
+                    new PlaylistItem(new BeatmapInfo
                     {
-                        OnlineID = realOnlineSetId,
+                        MD5Hash = realHash,
+                        OnlineID = realOnlineId,
+                        Metadata = new BeatmapMetadata(),
+                        BeatmapSet = new BeatmapSetInfo
+                        {
+                            OnlineID = realOnlineSetId,
+                        }
+                    })
+                    {
+                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID
                     }
-                })
-                {
-                    RulesetID = new OsuRuleset().RulesetInfo.OnlineID
-                });
+                ];
             });
 
             AddAssert("match has default beatmap", () => match.Beatmap.IsDefault);
@@ -181,17 +185,11 @@ namespace osu.Game.Tests.Visual.Playlists
             {
                 var originalBeatmap = new TestBeatmap(new OsuRuleset().RulesetInfo)
                 {
-                    BeatmapInfo =
-                    {
-                        OnlineID = realOnlineId,
-                        BeatmapSet =
-                        {
-                            OnlineID = realOnlineSetId
-                        }
-                    },
+                    BeatmapInfo = { OnlineID = realOnlineId },
                 };
 
                 Debug.Assert(originalBeatmap.BeatmapInfo.BeatmapSet != null);
+                originalBeatmap.BeatmapInfo.BeatmapSet.OnlineID = realOnlineSetId;
 
                 manager.Import(originalBeatmap.BeatmapInfo.BeatmapSet);
             });
@@ -201,7 +199,7 @@ namespace osu.Game.Tests.Visual.Playlists
 
         private void setupAndCreateRoom(Action<Room> room)
         {
-            AddStep("setup room", () => room(SelectedRoom!.Value));
+            AddStep("setup room", () => room(SelectedRoom.Value));
 
             AddStep("click create button", () =>
             {
@@ -215,8 +213,7 @@ namespace osu.Game.Tests.Visual.Playlists
             var beatmap = CreateBeatmap(new OsuRuleset().RulesetInfo);
 
             Debug.Assert(beatmap.BeatmapInfo.BeatmapSet != null);
-
-            importedBeatmap = manager.Import(beatmap.BeatmapInfo.BeatmapSet)?.Value.Detach();
+            importedBeatmap = manager.Import(beatmap.BeatmapInfo.BeatmapSet)!.Value.Detach();
         });
 
         private partial class TestPlaylistsRoomSubScreen : PlaylistsRoomSubScreen
@@ -226,8 +223,7 @@ namespace osu.Game.Tests.Visual.Playlists
             public new Bindable<WorkingBeatmap> Beatmap => base.Beatmap;
 
             [Resolved(canBeNull: true)]
-            [CanBeNull]
-            private IDialogOverlay dialogOverlay { get; set; }
+            private IDialogOverlay? dialogOverlay { get; set; }
 
             public TestPlaylistsRoomSubScreen(Room room)
                 : base(room)

osu.Game.Tests/Visual/UserInterface/TestSceneMainMenuButton.cs

@@ -53,13 +53,13 @@ namespace osu.Game.Tests.Visual.UserInterface
                         beatmap.OnlineID = 1001;
                         getRoomRequest.TriggerSuccess(new Room
                         {
-                            RoomID = { Value = 1234 },
+                            RoomID = 1234,
                             Playlist =
-                            {
+                            [
                                 new PlaylistItem(beatmap)
-                            },
-                            StartDate = { Value = DateTimeOffset.Now.AddMinutes(-5) },
-                            EndDate = { Value = DateTimeOffset.Now.AddSeconds(30) }
+                            ],
+                            StartDate = DateTimeOffset.Now.AddMinutes(-5),
+                            EndDate = DateTimeOffset.Now.AddSeconds(30)
                         });
                         return true;
 
@@ -131,13 +131,13 @@ namespace osu.Game.Tests.Visual.UserInterface
                         beatmap.OnlineID = 1001;
                         getRoomRequest.TriggerSuccess(new Room
                         {
-                            RoomID = { Value = 1234 },
+                            RoomID = 1234,
                             Playlist =
-                            {
+                            [
                                 new PlaylistItem(beatmap)
-                            },
-                            StartDate = { Value = DateTimeOffset.Now.AddMinutes(-50) },
-                            EndDate = { Value = DateTimeOffset.Now.AddSeconds(30) }
+                            ],
+                            StartDate = DateTimeOffset.Now.AddMinutes(-50),
+                            EndDate = DateTimeOffset.Now.AddSeconds(30)
                         });
                         return true;
 

osu.Game/.idea/.idea.osu.dir/.idea/.name

@@ -0,0 +1 @@
+osu

osu.Game/.idea/.idea.osu.dir/.idea/indexLayout.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="UserContentModel">
+    <attachedFolders />
+    <explicitIncludes />
+    <explicitExcludes />
+  </component>
+</project>

osu.Game/.idea/.idea.osu.dir/.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$/.." vcs="Git" />
+  </component>
+</project>

osu.Game/.idea/.idea.osu.dir/.idea/workspace.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ChangeListManager">
+    <list default="true" id="0959115c-c7d5-4a9d-b138-d34f47e6713a" name="Changes" comment="" />
+    <option name="SHOW_DIALOG" value="false" />
+    <option name="HIGHLIGHT_CONFLICTS" value="true" />
+    <option name="HIGHLIGHT_NON_ACTIVE_CHANGELIST" value="false" />
+    <option name="LAST_RESOLUTION" value="IGNORE" />
+  </component>
+  <component name="ProjectColorInfo"><![CDATA[{
+  "associatedIndex": 1
+}]]></component>
+  <component name="ProjectId" id="2p6efoueruThVmDy8XXhD8Ibwab" />
+  <component name="ProjectViewState">
+    <option name="autoscrollFromSource" value="true" />
+    <option name="autoscrollToSource" value="true" />
+    <option name="flattenPackages" value="true" />
+    <option name="hideEmptyMiddlePackages" value="true" />
+    <option name="showLibraryContents" value="true" />
+  </component>
+  <component name="SpellCheckerSettings" RuntimeDictionaries="0" Folders="0" CustomDictionaries="0" DefaultDictionary="application-level" UseSingleDictionary="true" transferred="true" />
+</project>

osu.Game/Beatmaps/Drawables/UpdateableBeatmapBackgroundSprite.cs

@@ -14,9 +14,17 @@ namespace osu.Game.Beatmaps.Drawables
     /// </summary>
     public partial class UpdateableBeatmapBackgroundSprite : ModelBackedDrawable<IBeatmapInfo>
     {
-        public readonly Bindable<IBeatmapInfo> Beatmap = new Bindable<IBeatmapInfo>();
+        public readonly Bindable<IBeatmapInfo?> Beatmap = new Bindable<IBeatmapInfo?>();
 
-        protected override double LoadDelay => 500;
+        /// <summary>
+        /// Delay before the background is loaded while on-screen.
+        /// </summary>
+        public double BackgroundLoadDelay { get; set; } = 500;
+
+        /// <summary>
+        /// Delay before the background is unloaded while off-screen.
+        /// </summary>
+        public double BackgroundUnloadDelay { get; set; } = 10000;
 
         [Resolved]
         private BeatmapManager beatmaps { get; set; } = null!;
@@ -29,10 +37,9 @@ namespace osu.Game.Beatmaps.Drawables
             this.beatmapSetCoverType = beatmapSetCoverType;
         }
 
-        /// <summary>
-        /// Delay before the background is unloaded while off-screen.
-        /// </summary>
-        protected virtual double UnloadDelay => 10000;
+        protected override double LoadDelay => BackgroundLoadDelay;
+
+        protected virtual double UnloadDelay => BackgroundUnloadDelay;
 
         protected override DelayedLoadWrapper CreateDelayedLoadWrapper(Func<Drawable> createContentFunc, double timeBeforeLoad) =>
             new DelayedLoadUnloadWrapper(createContentFunc, timeBeforeLoad, UnloadDelay) { RelativeSizeAxes = Axes.Both };

osu.Game/Online/Multiplayer/MultiplayerClient.cs

@@ -5,7 +5,6 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
-using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using osu.Framework.Allocation;
@@ -181,10 +180,10 @@ namespace osu.Game.Online.Multiplayer
 
             await joinOrLeaveTaskChain.Add(async () =>
             {
-                Debug.Assert(room.RoomID.Value != null);
+                Debug.Assert(room.RoomID != null);
 
                 // Join the server-side room.
-                var joinedRoom = await JoinRoom(room.RoomID.Value.Value, password ?? room.Password.Value).ConfigureAwait(false);
+                var joinedRoom = await JoinRoom(room.RoomID.Value, password ?? room.Password).ConfigureAwait(false);
                 Debug.Assert(joinedRoom != null);
 
                 // Populate users.
@@ -201,12 +200,11 @@ namespace osu.Game.Online.Multiplayer
 
                     Debug.Assert(joinedRoom.Playlist.Count > 0);
 
-                    APIRoom.Playlist.Clear();
-                    APIRoom.Playlist.AddRange(joinedRoom.Playlist.Select(item => new PlaylistItem(item)));
-                    APIRoom.CurrentPlaylistItem.Value = APIRoom.Playlist.Single(item => item.ID == joinedRoom.Settings.PlaylistItemId);
+                    APIRoom.Playlist = joinedRoom.Playlist.Select(item => new PlaylistItem(item)).ToArray();
+                    APIRoom.CurrentPlaylistItem = APIRoom.Playlist.Single(item => item.ID == joinedRoom.Settings.PlaylistItemId);
 
                     // The server will null out the end date upon the host joining the room, but the null value is never communicated to the client.
-                    APIRoom.EndDate.Value = null;
+                    APIRoom.EndDate = null;
 
                     Debug.Assert(LocalUser != null);
                     addUserToAPIRoom(LocalUser);
@@ -397,15 +395,15 @@ namespace osu.Game.Online.Multiplayer
                 switch (state)
                 {
                     case MultiplayerRoomState.Open:
-                        APIRoom.Status.Value = APIRoom.HasPassword.Value ? new RoomStatusOpenPrivate() : new RoomStatusOpen();
+                        APIRoom.Status = APIRoom.HasPassword ? new RoomStatusOpenPrivate() : new RoomStatusOpen();
                         break;
 
                     case MultiplayerRoomState.Playing:
-                        APIRoom.Status.Value = new RoomStatusPlaying();
+                        APIRoom.Status = new RoomStatusPlaying();
                         break;
 
                     case MultiplayerRoomState.Closed:
-                        APIRoom.Status.Value = new RoomStatusEnded();
+                        APIRoom.Status = new RoomStatusEnded();
                         break;
                 }
 
@@ -459,7 +457,7 @@ namespace osu.Game.Online.Multiplayer
             if (apiUser == null || apiRoom == null) return;
 
             PostNotification?.Invoke(
-                new UserAvatarNotification(apiUser, NotificationsStrings.InvitedYouToTheMultiplayer(apiUser.Username, apiRoom.Name.Value))
+                new UserAvatarNotification(apiUser, NotificationsStrings.InvitedYouToTheMultiplayer(apiUser.Username, apiRoom.Name))
                 {
                     Activated = () =>
                     {
@@ -487,12 +485,12 @@ namespace osu.Game.Online.Multiplayer
         {
             Debug.Assert(APIRoom != null);
 
-            APIRoom.RecentParticipants.Add(user.User ?? new APIUser
+            APIRoom.RecentParticipants = APIRoom.RecentParticipants.Append(user.User ?? new APIUser
             {
                 Id = user.UserID,
                 Username = "[Unresolved]"
-            });
-            APIRoom.ParticipantCount.Value++;
+            }).ToArray();
+            APIRoom.ParticipantCount++;
         }
 
         private Task handleUserLeft(MultiplayerRoomUser user, Action<MultiplayerRoomUser>? callback)
@@ -506,8 +504,8 @@ namespace osu.Game.Online.Multiplayer
                 PlayingUserIds.Remove(user.UserID);
 
                 Debug.Assert(APIRoom != null);
-                APIRoom.RecentParticipants.RemoveAll(u => u.Id == user.UserID);
-                APIRoom.ParticipantCount.Value--;
+                APIRoom.RecentParticipants = APIRoom.RecentParticipants.Where(u => u.Id != user.UserID).ToArray();
+                APIRoom.ParticipantCount--;
 
                 callback?.Invoke(user);
                 RoomUpdated?.Invoke();
@@ -528,7 +526,7 @@ namespace osu.Game.Online.Multiplayer
                 var user = Room.Users.FirstOrDefault(u => u.UserID == userId);
 
                 Room.Host = user;
-                APIRoom.Host.Value = user?.User;
+                APIRoom.Host = user?.User;
 
                 RoomUpdated?.Invoke();
             }, false);
@@ -734,7 +732,7 @@ namespace osu.Game.Online.Multiplayer
                 Debug.Assert(APIRoom != null);
 
                 Room.Playlist.Add(item);
-                APIRoom.Playlist.Add(new PlaylistItem(item));
+                APIRoom.Playlist = APIRoom.Playlist.Append(new PlaylistItem(item)).ToArray();
 
                 ItemAdded?.Invoke(item);
                 RoomUpdated?.Invoke();
@@ -753,7 +751,7 @@ namespace osu.Game.Online.Multiplayer
                 Debug.Assert(APIRoom != null);
 
                 Room.Playlist.Remove(Room.Playlist.Single(existing => existing.ID == playlistItemId));
-                APIRoom.Playlist.RemoveAll(existing => existing.ID == playlistItemId);
+                APIRoom.Playlist = APIRoom.Playlist.Where(i => i.ID != playlistItemId).ToArray();
 
                 Debug.Assert(Room.Playlist.Count > 0);
 
@@ -771,30 +769,10 @@ namespace osu.Game.Online.Multiplayer
                 if (Room == null)
                     return;
 
-                try
-                {
-                    Debug.Assert(APIRoom != null);
+                Debug.Assert(APIRoom != null);
 
-                    Room.Playlist[Room.Playlist.IndexOf(Room.Playlist.Single(existing => existing.ID == item.ID))] = item;
-
-                    int existingIndex = APIRoom.Playlist.IndexOf(APIRoom.Playlist.Single(existing => existing.ID == item.ID));
-
-                    APIRoom.Playlist.RemoveAt(existingIndex);
-                    APIRoom.Playlist.Insert(existingIndex, new PlaylistItem(item));
-                }
-                catch (Exception ex)
-                {
-                    // Temporary code to attempt to figure out long-term failing tests.
-                    StringBuilder exceptionText = new StringBuilder();
-
-                    exceptionText.AppendLine("MultiplayerClient test failure investigation");
-                    exceptionText.AppendLine($"Exception                : {ex.ToString()}");
-                    exceptionText.AppendLine($"Lookup                   : {item.ID}");
-                    exceptionText.AppendLine($"Items in Room.Playlist   : {string.Join(',', Room.Playlist.Select(i => i.ID))}");
-                    exceptionText.AppendLine($"Items in APIRoom.Playlist: {string.Join(',', APIRoom!.Playlist.Select(i => i.ID))}");
-
-                    throw new AggregateException(exceptionText.ToString());
-                }
+                Room.Playlist[Room.Playlist.IndexOf(Room.Playlist.Single(existing => existing.ID == item.ID))] = item;
+                APIRoom.Playlist = APIRoom.Playlist.Select((pi, i) => pi.ID == item.ID ? new PlaylistItem(item) : APIRoom.Playlist[i]).ToArray();
 
                 ItemChanged?.Invoke(item);
                 RoomUpdated?.Invoke();
@@ -841,14 +819,14 @@ namespace osu.Game.Online.Multiplayer
 
             // Update a few properties of the room instantaneously.
             Room.Settings = settings;
-            APIRoom.Name.Value = Room.Settings.Name;
-            APIRoom.Password.Value = Room.Settings.Password;
-            APIRoom.Status.Value = string.IsNullOrEmpty(Room.Settings.Password) ? new RoomStatusOpen() : new RoomStatusOpenPrivate();
-            APIRoom.Type.Value = Room.Settings.MatchType;
-            APIRoom.QueueMode.Value = Room.Settings.QueueMode;
-            APIRoom.AutoStartDuration.Value = Room.Settings.AutoStartDuration;
-            APIRoom.CurrentPlaylistItem.Value = APIRoom.Playlist.Single(item => item.ID == settings.PlaylistItemId);
-            APIRoom.AutoSkip.Value = Room.Settings.AutoSkip;
+            APIRoom.Name = Room.Settings.Name;
+            APIRoom.Password = Room.Settings.Password;
+            APIRoom.Status = string.IsNullOrEmpty(Room.Settings.Password) ? new RoomStatusOpen() : new RoomStatusOpenPrivate();
+            APIRoom.Type = Room.Settings.MatchType;
+            APIRoom.QueueMode = Room.Settings.QueueMode;
+            APIRoom.AutoStartDuration = Room.Settings.AutoStartDuration;
+            APIRoom.CurrentPlaylistItem = APIRoom.Playlist.Single(item => item.ID == settings.PlaylistItemId);
+            APIRoom.AutoSkip = Room.Settings.AutoSkip;
 
             RoomUpdated?.Invoke();
         }

osu.Game/Online/Rooms/GetRoomsRequest.cs

@@ -44,12 +44,12 @@ namespace osu.Game.Online.Rooms
                 // API doesn't populate status so let's do it here.
                 foreach (var room in Response)
                 {
-                    if (room.EndDate.Value != null && DateTimeOffset.Now >= room.EndDate.Value)
-                        room.Status.Value = new RoomStatusEnded();
-                    else if (room.HasPassword.Value)
-                        room.Status.Value = new RoomStatusOpenPrivate();
+                    if (room.EndDate != null && DateTimeOffset.Now >= room.EndDate)
+                        room.Status = new RoomStatusEnded();
+                    else if (room.HasPassword)
+                        room.Status = new RoomStatusOpenPrivate();
                     else
-                        room.Status.Value = new RoomStatusOpen();
+                        room.Status = new RoomStatusOpen();
                 }
             }
         }

osu.Game/Online/Rooms/JoinRoomRequest.cs

@@ -27,6 +27,6 @@ namespace osu.Game.Online.Rooms
             return req;
         }
 
-        protected override string Target => $@"rooms/{Room.RoomID.Value}/users/{User!.Id}";
+        protected override string Target => $@"rooms/{Room.RoomID}/users/{User!.Id}";
     }
 }

osu.Game/Online/Rooms/PartRoomRequest.cs

@@ -23,6 +23,6 @@ namespace osu.Game.Online.Rooms
             return req;
         }
 
-        protected override string Target => $"rooms/{room.RoomID.Value}/users/{User!.Id}";
+        protected override string Target => $"rooms/{room.RoomID}/users/{User!.Id}";
     }
 }

osu.Game/Online/Rooms/PlaylistExtensions.cs

@@ -5,7 +5,6 @@ using System.Collections.Generic;
 using System.Linq;
 using Humanizer;
 using Humanizer.Localisation;
-using osu.Framework.Bindables;
 using osu.Game.Rulesets;
 using osu.Game.Utils;
 
@@ -30,7 +29,7 @@ namespace osu.Game.Online.Rooms
         /// or the last-played <see cref="PlaylistItem"/> if all items are expired,
         /// or <see langword="null"/> if <paramref name="playlist"/> was empty.
         /// </summary>
-        public static PlaylistItem? GetCurrentItem(this ICollection<PlaylistItem> playlist)
+        public static PlaylistItem? GetCurrentItem(this IReadOnlyCollection<PlaylistItem> playlist)
         {
             if (playlist.Count == 0)
                 return null;
@@ -43,7 +42,7 @@ namespace osu.Game.Online.Rooms
         /// <summary>
         /// Returns the total duration from the <see cref="PlaylistItem"/> in playlist order from the supplied <paramref name="playlist"/>,
         /// </summary>
-        public static string GetTotalDuration(this BindableList<PlaylistItem> playlist, RulesetStore rulesetStore) =>
+        public static string GetTotalDuration(this IReadOnlyList<PlaylistItem> playlist, RulesetStore rulesetStore) =>
             playlist.Select(p =>
             {
                 double rate = 1;

osu.Game/Online/Rooms/PlaylistItem.cs

@@ -120,18 +120,21 @@ namespace osu.Game.Online.Rooms
 
         #endregion
 
-        public PlaylistItem With(Optional<IBeatmapInfo> beatmap = default, Optional<ushort?> playlistOrder = default) => new PlaylistItem(beatmap.GetOr(Beatmap))
+        public PlaylistItem With(Optional<long> id = default, Optional<IBeatmapInfo> beatmap = default, Optional<ushort?> playlistOrder = default)
         {
-            ID = ID,
-            OwnerID = OwnerID,
-            RulesetID = RulesetID,
-            Expired = Expired,
-            PlaylistOrder = playlistOrder.GetOr(PlaylistOrder),
-            PlayedAt = PlayedAt,
-            AllowedMods = AllowedMods,
-            RequiredMods = RequiredMods,
-            valid = { Value = Valid.Value },
-        };
+            return new PlaylistItem(beatmap.GetOr(Beatmap))
+            {
+                ID = id.GetOr(ID),
+                OwnerID = OwnerID,
+                RulesetID = RulesetID,
+                Expired = Expired,
+                PlaylistOrder = playlistOrder.GetOr(PlaylistOrder),
+                PlayedAt = PlayedAt,
+                AllowedMods = AllowedMods,
+                RequiredMods = RequiredMods,
+                valid = { Value = Valid.Value },
+            };
+        }
 
         public bool Equals(PlaylistItem? other)
             => ID == other?.ID

osu.Game/Online/Rooms/Room.cs

@@ -1,13 +1,12 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
+using System.Collections.Generic;
+using System.ComponentModel;
 using System.Linq;
+using System.Runtime.CompilerServices;
 using Newtonsoft.Json;
-using osu.Framework.Allocation;
-using osu.Framework.Bindables;
 using osu.Game.IO.Serialization.Converters;
 using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Online.Multiplayer;
@@ -16,162 +15,332 @@ using osu.Game.Online.Rooms.RoomStatuses;
 namespace osu.Game.Online.Rooms
 {
     [JsonObject(MemberSerialization.OptIn)]
-    public partial class Room : IDependencyInjectionCandidate
+    public partial class Room : INotifyPropertyChanged
     {
-        [Cached]
-        [JsonProperty("id")]
-        public readonly Bindable<long?> RoomID = new Bindable<long?>();
+        public event PropertyChangedEventHandler? PropertyChanged;
 
-        [Cached]
-        [JsonProperty("name")]
-        public readonly Bindable<string> Name = new Bindable<string>();
-
-        [Cached]
-        [JsonProperty("host")]
-        public readonly Bindable<APIUser> Host = new Bindable<APIUser>();
-
-        [Cached]
-        [JsonProperty("playlist")]
-        public readonly BindableList<PlaylistItem> Playlist = new BindableList<PlaylistItem>();
-
-        [Cached]
-        [JsonProperty("channel_id")]
-        public readonly Bindable<int> ChannelId = new Bindable<int>();
-
-        [JsonProperty("current_playlist_item")]
-        [Cached]
-        public readonly Bindable<PlaylistItem> CurrentPlaylistItem = new Bindable<PlaylistItem>();
-
-        [JsonProperty("playlist_item_stats")]
-        [Cached]
-        public readonly Bindable<RoomPlaylistItemStats> PlaylistItemStats = new Bindable<RoomPlaylistItemStats>();
-
-        [JsonProperty("difficulty_range")]
-        [Cached]
-        public readonly Bindable<RoomDifficultyRange> DifficultyRange = new Bindable<RoomDifficultyRange>();
-
-        [Cached]
-        public readonly Bindable<RoomCategory> Category = new Bindable<RoomCategory>();
-
-        // Todo: osu-framework bug (https://github.com/ppy/osu-framework/issues/4106)
-        [JsonProperty("category")]
-        [JsonConverter(typeof(SnakeCaseStringEnumConverter))]
-        private RoomCategory category
+        /// <summary>
+        /// The online room ID. Will be <c>null</c> while the room has not yet been created.
+        /// </summary>
+        public long? RoomID
         {
-            get => Category.Value;
-            set => Category.Value = value;
+            get => roomId;
+            set => SetField(ref roomId, value);
         }
 
-        [Cached]
-        public readonly Bindable<int?> MaxAttempts = new Bindable<int?>();
-
-        [Cached]
-        public readonly Bindable<RoomStatus> Status = new Bindable<RoomStatus>(new RoomStatusOpen());
-
-        [Cached]
-        public readonly Bindable<RoomAvailability> Availability = new Bindable<RoomAvailability>();
-
-        [Cached]
-        public readonly Bindable<MatchType> Type = new Bindable<MatchType>();
-
-        // Todo: osu-framework bug (https://github.com/ppy/osu-framework/issues/4106)
-        [JsonConverter(typeof(SnakeCaseStringEnumConverter))]
-        [JsonProperty("type")]
-        private MatchType type
+        /// <summary>
+        /// The room name.
+        /// </summary>
+        public string Name
         {
-            get => Type.Value;
-            set => Type.Value = value;
+            get => name;
+            set => SetField(ref name, value);
         }
 
-        [Cached]
-        public readonly Bindable<QueueMode> QueueMode = new Bindable<QueueMode>();
-
-        [JsonConverter(typeof(SnakeCaseStringEnumConverter))]
-        [JsonProperty("queue_mode")]
-        private QueueMode queueMode
+        /// <summary>
+        /// Sets the room password. Will be <c>null</c> after the room is created.
+        /// </summary>
+        /// <remarks>
+        /// To check if the room has a password, use <see cref="HasPassword"/>.
+        /// </remarks>
+        public string? Password
         {
-            get => QueueMode.Value;
-            set => QueueMode.Value = value;
-        }
-
-        [Cached]
-        public readonly Bindable<TimeSpan> AutoStartDuration = new Bindable<TimeSpan>();
-
-        [JsonProperty("auto_start_duration")]
-        private ushort autoStartDuration
-        {
-            get => (ushort)AutoStartDuration.Value.TotalSeconds;
-            set => AutoStartDuration.Value = TimeSpan.FromSeconds(value);
-        }
-
-        [Cached]
-        public readonly Bindable<int?> MaxParticipants = new Bindable<int?>();
-
-        [Cached]
-        [JsonProperty("current_user_score")]
-        public readonly Bindable<PlaylistAggregateScore> UserScore = new Bindable<PlaylistAggregateScore>();
-
-        [JsonProperty("has_password")]
-        public readonly Bindable<bool> HasPassword = new Bindable<bool>();
-
-        [Cached]
-        [JsonProperty("recent_participants")]
-        public readonly BindableList<APIUser> RecentParticipants = new BindableList<APIUser>();
-
-        [Cached]
-        [JsonProperty("participant_count")]
-        public readonly Bindable<int> ParticipantCount = new Bindable<int>();
-
-        #region Properties only used for room creation request
-
-        [Cached(Name = nameof(Password))]
-        [JsonProperty("password")]
-        public readonly Bindable<string> Password = new Bindable<string>();
-
-        [Cached]
-        public readonly Bindable<TimeSpan?> Duration = new Bindable<TimeSpan?>();
-
-        [JsonProperty("duration")]
-        private int? duration
-        {
-            get => (int?)Duration.Value?.TotalMinutes;
+            get => password;
             set
             {
-                if (value == null)
-                    Duration.Value = null;
-                else
-                    Duration.Value = TimeSpan.FromMinutes(value.Value);
+                SetField(ref password, value);
+                HasPassword = !string.IsNullOrEmpty(value);
             }
         }
 
-        #endregion
+        /// <summary>
+        /// Whether the room has a password.
+        /// </summary>
+        /// <remarks>
+        /// To set a password, use <see cref="Password"/>.
+        /// </remarks>
+        [JsonProperty("has_password")]
+        public bool HasPassword
+        {
+            get => hasPassword;
+            private set => SetField(ref hasPassword, value);
+        }
+
+        /// <summary>
+        /// The room host. Will be <c>null</c> while the room has not yet been created.
+        /// </summary>
+        public APIUser? Host
+        {
+            get => host;
+            set => SetField(ref host, value);
+        }
+
+        /// <summary>
+        /// The room category.
+        /// </summary>
+        public RoomCategory Category
+        {
+            get => category;
+            set => SetField(ref category, value);
+        }
+
+        /// <summary>
+        /// The duration for which the room will be open. Will be <c>null</c> after the room is created.
+        /// </summary>
+        /// <remarks>
+        /// To check the room end time, use <see cref="EndDate"/>.
+        /// </remarks>
+        public TimeSpan? Duration
+        {
+            get => duration == null ? null : TimeSpan.FromMinutes(duration.Value);
+            set => SetField(ref duration, value == null ? null : (int)value.Value.TotalMinutes);
+        }
+
+        /// <summary>
+        /// The date at which the room was opened. Will be <c>null</c> while the room has not yet been created.
+        /// </summary>
+        public DateTimeOffset? StartDate
+        {
+            get => startDate;
+            set => SetField(ref startDate, value);
+        }
+
+        /// <summary>
+        /// The date at which the room will be closed.
+        /// </summary>
+        /// <remarks>
+        /// To set the room duration, use <see cref="Duration"/>.
+        /// </remarks>
+        public DateTimeOffset? EndDate
+        {
+            get => endDate;
+            set => SetField(ref endDate, value);
+        }
+
+        /// <summary>
+        /// The maximum number of users allowed in the room.
+        /// </summary>
+        public int? MaxParticipants
+        {
+            get => maxParticipants;
+            set => SetField(ref maxParticipants, value);
+        }
+
+        /// <summary>
+        /// The current number of users in the room.
+        /// </summary>
+        public int ParticipantCount
+        {
+            get => participantCount;
+            set => SetField(ref participantCount, value);
+        }
+
+        /// <summary>
+        /// The set of most recent participants in the room.
+        /// </summary>
+        public IReadOnlyList<APIUser> RecentParticipants
+        {
+            get => recentParticipants;
+            set => SetList(ref recentParticipants, value);
+        }
+
+        /// <summary>
+        /// The match type.
+        /// </summary>
+        public MatchType Type
+        {
+            get => type;
+            set => SetField(ref type, value);
+        }
+
+        /// <summary>
+        /// The maximum number of attempts on the playlist. Only valid for playlist rooms.
+        /// </summary>
+        public int? MaxAttempts
+        {
+            get => maxAttempts;
+            set => SetField(ref maxAttempts, value);
+        }
+
+        /// <summary>
+        /// The room playlist.
+        /// </summary>
+        public IReadOnlyList<PlaylistItem> Playlist
+        {
+            get => playlist;
+            set => SetList(ref playlist, value);
+        }
+
+        /// <summary>
+        /// Describes the items in the playlist.
+        /// </summary>
+        public RoomPlaylistItemStats? PlaylistItemStats
+        {
+            get => playlistItemStats;
+            set => SetField(ref playlistItemStats, value);
+        }
+
+        /// <summary>
+        /// Describes the range of difficulty of the room.
+        /// </summary>
+        public RoomDifficultyRange? DifficultyRange
+        {
+            get => difficultyRange;
+            set => SetField(ref difficultyRange, value);
+        }
+
+        /// <summary>
+        /// The playlist queueing mode. Only valid for multiplayer rooms.
+        /// </summary>
+        public QueueMode QueueMode
+        {
+            get => queueMode;
+            set => SetField(ref queueMode, value);
+        }
+
+        /// <summary>
+        /// Whether to automatically skip map intros. Only valid for multiplayer rooms.
+        /// </summary>
+        public bool AutoSkip
+        {
+            get => autoSkip;
+            set => SetField(ref autoSkip, value);
+        }
+
+        /// <summary>
+        /// The amount of time before the match is automatically started. Only valid for multiplayer rooms.
+        /// </summary>
+        public TimeSpan AutoStartDuration
+        {
+            get => TimeSpan.FromSeconds(autoStartDuration);
+            set => SetField(ref autoStartDuration, (ushort)value.TotalSeconds);
+        }
+
+        /// <summary>
+        /// Provides some extra scoring statistics for the local user in the room.
+        /// </summary>
+        public PlaylistAggregateScore? UserScore
+        {
+            get => userScore;
+            set => SetField(ref userScore, value);
+        }
+
+        /// <summary>
+        /// Represents the current item selected within the room.
+        /// </summary>
+        /// <remarks>
+        /// Only valid for room listing requests (i.e. in the lounge screen), and may not be valid while inside the room.
+        /// </remarks>
+        public PlaylistItem? CurrentPlaylistItem
+        {
+            get => currentPlaylistItem;
+            set => SetField(ref currentPlaylistItem, value);
+        }
+
+        /// <summary>
+        /// The chat channel id for the room. Will be <c>0</c> while the room has not yet been created.
+        /// </summary>
+        public int ChannelId
+        {
+            get => channelId;
+            private set => SetField(ref channelId, value);
+        }
+
+        /// <summary>
+        /// The current room status.
+        /// </summary>
+        public RoomStatus Status
+        {
+            get => status;
+            set => SetField(ref status, value);
+        }
+
+        /// <summary>
+        /// Describes which players are able to join the room.
+        /// </summary>
+        public RoomAvailability Availability
+        {
+            get => availability;
+            set => SetField(ref availability, value);
+        }
+
+        [JsonProperty("id")]
+        private long? roomId;
+
+        [JsonProperty("name")]
+        private string name = string.Empty;
+
+        [JsonProperty("password")]
+        private string? password;
+
+        // Not serialised (internal use only).
+        private bool hasPassword;
+
+        [JsonProperty("host")]
+        private APIUser? host;
+
+        [JsonProperty("category")]
+        [JsonConverter(typeof(SnakeCaseStringEnumConverter))]
+        private RoomCategory category;
+
+        [JsonProperty("duration")]
+        private int? duration;
 
-        // Only supports retrieval for now
-        [Cached]
         [JsonProperty("starts_at")]
-        public readonly Bindable<DateTimeOffset?> StartDate = new Bindable<DateTimeOffset?>();
+        private DateTimeOffset? startDate;
 
-        // Only supports retrieval for now
-        [Cached]
         [JsonProperty("ends_at")]
-        public readonly Bindable<DateTimeOffset?> EndDate = new Bindable<DateTimeOffset?>();
+        private DateTimeOffset? endDate;
+
+        // Not yet serialised (not implemented).
+        private int? maxParticipants;
+
+        [JsonProperty("participant_count")]
+        private int participantCount;
+
+        [JsonProperty("recent_participants")]
+        private IReadOnlyList<APIUser> recentParticipants = [];
 
-        // Todo: Find a better way to do this (https://github.com/ppy/osu-framework/issues/1930)
         [JsonProperty("max_attempts", DefaultValueHandling = DefaultValueHandling.Ignore)]
-        private int? maxAttempts
-        {
-            get => MaxAttempts.Value;
-            set => MaxAttempts.Value = value;
-        }
+        private int? maxAttempts;
+
+        [JsonProperty("playlist")]
+        private IReadOnlyList<PlaylistItem> playlist = [];
+
+        [JsonProperty("playlist_item_stats")]
+        private RoomPlaylistItemStats? playlistItemStats;
+
+        [JsonProperty("difficulty_range")]
+        private RoomDifficultyRange? difficultyRange;
+
+        [JsonConverter(typeof(SnakeCaseStringEnumConverter))]
+        [JsonProperty("type")]
+        private MatchType type;
+
+        [JsonConverter(typeof(SnakeCaseStringEnumConverter))]
+        [JsonProperty("queue_mode")]
+        private QueueMode queueMode;
 
-        [Cached]
         [JsonProperty("auto_skip")]
-        public readonly Bindable<bool> AutoSkip = new Bindable<bool>();
+        private bool autoSkip;
 
-        public Room()
-        {
-            Password.BindValueChanged(p => HasPassword.Value = !string.IsNullOrEmpty(p.NewValue));
-        }
+        [JsonProperty("auto_start_duration")]
+        private ushort autoStartDuration;
+
+        [JsonProperty("current_user_score")]
+        private PlaylistAggregateScore? userScore;
+
+        [JsonProperty("current_playlist_item")]
+        private PlaylistItem? currentPlaylistItem;
+
+        [JsonProperty("channel_id")]
+        private int channelId;
+
+        // Not serialised (see: GetRoomsRequest).
+        private RoomStatus status = new RoomStatusOpen();
+
+        // Not yet serialised (not implemented).
+        private RoomAvailability availability;
 
         /// <summary>
         /// Copies values from another <see cref="Room"/> into this one.
@@ -182,43 +351,34 @@ namespace osu.Game.Online.Rooms
         /// <param name="other">The <see cref="Room"/> to copy values from.</param>
         public void CopyFrom(Room other)
         {
-            RoomID.Value = other.RoomID.Value;
-            Name.Value = other.Name.Value;
+            RoomID = other.RoomID;
+            Name = other.Name;
 
-            Category.Value = other.Category.Value;
+            Category = other.Category;
 
-            if (other.Host.Value != null && Host.Value?.Id != other.Host.Value.Id)
-                Host.Value = other.Host.Value;
+            if (other.Host != null && Host?.Id != other.Host.Id)
+                Host = other.Host;
 
-            ChannelId.Value = other.ChannelId.Value;
-            Status.Value = other.Status.Value;
-            Availability.Value = other.Availability.Value;
-            HasPassword.Value = other.HasPassword.Value;
-            Type.Value = other.Type.Value;
-            MaxParticipants.Value = other.MaxParticipants.Value;
-            ParticipantCount.Value = other.ParticipantCount.Value;
-            EndDate.Value = other.EndDate.Value;
-            UserScore.Value = other.UserScore.Value;
-            QueueMode.Value = other.QueueMode.Value;
-            AutoStartDuration.Value = other.AutoStartDuration.Value;
-            DifficultyRange.Value = other.DifficultyRange.Value;
-            PlaylistItemStats.Value = other.PlaylistItemStats.Value;
-            CurrentPlaylistItem.Value = other.CurrentPlaylistItem.Value;
-            AutoSkip.Value = other.AutoSkip.Value;
+            ChannelId = other.ChannelId;
+            Status = other.Status;
+            Availability = other.Availability;
+            HasPassword = other.HasPassword;
+            Type = other.Type;
+            MaxParticipants = other.MaxParticipants;
+            ParticipantCount = other.ParticipantCount;
+            EndDate = other.EndDate;
+            UserScore = other.UserScore;
+            QueueMode = other.QueueMode;
+            AutoStartDuration = other.AutoStartDuration;
+            DifficultyRange = other.DifficultyRange;
+            PlaylistItemStats = other.PlaylistItemStats;
+            CurrentPlaylistItem = other.CurrentPlaylistItem;
+            AutoSkip = other.AutoSkip;
 
             other.RemoveExpiredPlaylistItems();
 
-            if (!Playlist.SequenceEqual(other.Playlist))
-            {
-                Playlist.Clear();
-                Playlist.AddRange(other.Playlist);
-            }
-
-            if (!RecentParticipants.SequenceEqual(other.RecentParticipants))
-            {
-                RecentParticipants.Clear();
-                RecentParticipants.AddRange(other.RecentParticipants);
-            }
+            Playlist = other.Playlist;
+            RecentParticipants = other.RecentParticipants;
         }
 
         public void RemoveExpiredPlaylistItems()
@@ -226,8 +386,8 @@ namespace osu.Game.Online.Rooms
             // Todo: This is not the best way/place to do this, but the intention is to display all playlist items when the room has ended,
             // and display only the non-expired playlist items while the room is still active. In order to achieve this, all expired items are removed from the source Room.
             // More refactoring is required before this can be done locally instead - DrawableRoomPlaylist is currently directly bound to the playlist to display items in the room.
-            if (!(Status.Value is RoomStatusEnded))
-                Playlist.RemoveAll(i => i.Expired);
+            if (Status is not RoomStatusEnded)
+                Playlist = Playlist.Where(i => !i.Expired).ToArray();
         }
 
         [JsonObject(MemberSerialization.OptIn)]
@@ -240,7 +400,7 @@ namespace osu.Game.Online.Rooms
             public int CountTotal;
 
             [JsonProperty("ruleset_ids")]
-            public int[] RulesetIDs;
+            public int[] RulesetIDs = [];
         }
 
         [JsonObject(MemberSerialization.OptIn)]
@@ -252,5 +412,28 @@ namespace osu.Game.Online.Rooms
             [JsonProperty("max")]
             public double Max;
         }
+
+        protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null!)
+            => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+
+        protected bool SetList<T>(ref IReadOnlyList<T> list, IReadOnlyList<T> value, [CallerMemberName] string propertyName = null!)
+        {
+            if (list.SequenceEqual(value))
+                return false;
+
+            list = value;
+            OnPropertyChanged(propertyName);
+            return true;
+        }
+
+        protected bool SetField<T>(ref T field, T value, [CallerMemberName] string propertyName = null!)
+        {
+            if (EqualityComparer<T>.Default.Equals(field, value))
+                return false;
+
+            field = value;
+            OnPropertyChanged(propertyName);
+            return true;
+        }
     }
 }

osu.Game/Screens/Menu/DailyChallengeButton.cs

@@ -156,15 +156,15 @@ namespace osu.Game.Screens.Menu
                     Room = room;
                     cover.OnlineInfo = TooltipContent = room.Playlist.FirstOrDefault()?.Beatmap.BeatmapSet as APIBeatmapSet;
 
-                    if (room.StartDate.Value != null && room.RoomID.Value != lastDailyChallengeRoomID)
+                    if (room.StartDate != null && room.RoomID != lastDailyChallengeRoomID)
                     {
-                        lastDailyChallengeRoomID = room.RoomID.Value;
+                        lastDailyChallengeRoomID = room.RoomID;
 
                         // new challenge is live, reset intro played static.
                         statics.SetValue(Static.DailyChallengeIntroPlayed, false);
 
                         // we only want to notify the user if the new challenge just went live.
-                        if (Math.Abs((DateTimeOffset.Now - room.StartDate.Value!.Value).TotalSeconds) < 1800)
+                        if (Math.Abs((DateTimeOffset.Now - room.StartDate.Value).TotalSeconds) < 1800)
                             notificationOverlay?.Post(new NewDailyChallengeNotification(room));
                     }
 
@@ -180,7 +180,7 @@ namespace osu.Game.Screens.Menu
             if (Room == null)
                 return;
 
-            var remaining = (Room.EndDate.Value - DateTimeOffset.Now) ?? TimeSpan.Zero;
+            var remaining = (Room.EndDate - DateTimeOffset.Now) ?? TimeSpan.Zero;
 
             if (remaining <= TimeSpan.Zero)
             {

osu.Game/Screens/OnlinePlay/Components/BeatmapTitle.cs

@@ -1,32 +1,40 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.ComponentModel;
 using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
 using osu.Framework.Localisation;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
 using osu.Game.Online.Chat;
+using osu.Game.Online.Rooms;
 
 namespace osu.Game.Screens.OnlinePlay.Components
 {
-    public partial class BeatmapTitle : OnlinePlayComposite
+    public partial class BeatmapTitle : CompositeDrawable
     {
+        private readonly Room room;
         private readonly LinkFlowContainer textFlow;
 
-        public BeatmapTitle()
-        {
-            AutoSizeAxes = Axes.Both;
+        [Resolved]
+        private OsuColour colours { get; set; } = null!;
 
+        public BeatmapTitle(Room room)
+        {
+            this.room = room;
+
+            AutoSizeAxes = Axes.Both;
             InternalChild = textFlow = new LinkFlowContainer { AutoSizeAxes = Axes.Both };
         }
 
-        [BackgroundDependencyLoader]
-        private void load()
+        protected override void LoadComplete()
         {
-            Playlist.CollectionChanged += (_, _) => updateText();
+            base.LoadComplete();
 
+            room.PropertyChanged += onRoomPropertyChanged;
             updateText();
         }
 
@@ -46,8 +54,11 @@ namespace osu.Game.Screens.OnlinePlay.Components
             }
         }
 
-        [Resolved]
-        private OsuColour colours { get; set; } = null!;
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(Room.Playlist))
+                updateText();
+        }
 
         private void updateText()
         {
@@ -56,7 +67,7 @@ namespace osu.Game.Screens.OnlinePlay.Components
 
             textFlow.Clear();
 
-            var beatmap = Playlist.FirstOrDefault()?.Beatmap;
+            var beatmap = room.Playlist.FirstOrDefault()?.Beatmap;
 
             if (beatmap == null)
             {
@@ -78,5 +89,11 @@ namespace osu.Game.Screens.OnlinePlay.Components
                 textFlow.AddLink(title, LinkAction.OpenBeatmap, beatmap.OnlineID.ToString(), "Open beatmap");
             }
         }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
+        }
     }
 }

osu.Game/Screens/OnlinePlay/Components/ListingPollingComponent.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System.Linq;
 using System.Threading.Tasks;
 using osu.Framework.Allocation;
@@ -35,7 +33,7 @@ namespace osu.Game.Screens.OnlinePlay.Components
             });
         }
 
-        private GetRoomsRequest lastPollRequest;
+        private GetRoomsRequest? lastPollRequest;
 
         protected override Task Poll()
         {
@@ -53,11 +51,11 @@ namespace osu.Game.Screens.OnlinePlay.Components
 
             req.Success += result =>
             {
-                result = result.Where(r => r.Category.Value != RoomCategory.DailyChallenge).ToList();
+                result = result.Where(r => r.Category != RoomCategory.DailyChallenge).ToList();
 
                 foreach (var existing in RoomManager.Rooms.ToArray())
                 {
-                    if (result.All(r => r.RoomID.Value != existing.RoomID.Value))
+                    if (result.All(r => r.RoomID != existing.RoomID))
                         RoomManager.RemoveRoom(existing);
                 }
 

osu.Game/Screens/OnlinePlay/Components/MatchBeatmapDetailArea.cs

@@ -1,12 +1,9 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
+using System.ComponentModel;
 using System.Linq;
-using osu.Framework.Allocation;
-using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Game.Graphics.UserInterfaceV2;
@@ -14,23 +11,22 @@ using osu.Game.Online.Rooms;
 using osu.Game.Screens.OnlinePlay.Playlists;
 using osu.Game.Screens.Select;
 using osuTK;
+using Container = osu.Framework.Graphics.Containers.Container;
 
 namespace osu.Game.Screens.OnlinePlay.Components
 {
     public partial class MatchBeatmapDetailArea : BeatmapDetailArea
     {
-        public Action CreateNewItem;
-
-        public readonly Bindable<PlaylistItem> SelectedItem = new Bindable<PlaylistItem>();
-
-        [Resolved(typeof(Room))]
-        protected BindableList<PlaylistItem> Playlist { get; private set; }
+        public Action? CreateNewItem;
 
+        private readonly Room room;
         private readonly GridContainer playlistArea;
         private readonly DrawableRoomPlaylist playlist;
 
-        public MatchBeatmapDetailArea()
+        public MatchBeatmapDetailArea(Room room)
         {
+            this.room = room;
+
             Add(playlistArea = new GridContainer
             {
                 RelativeSizeAxes = Axes.Both,
@@ -72,10 +68,21 @@ namespace osu.Game.Screens.OnlinePlay.Components
         {
             base.LoadComplete();
 
-            playlist.Items.BindTo(Playlist);
-            playlist.SelectedItem.BindTo(SelectedItem);
+            playlist.Items.BindCollectionChanged((_, __) => room.Playlist = playlist.Items.ToArray());
+
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateRoomPlaylist();
         }
 
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(Room.Playlist))
+                updateRoomPlaylist();
+        }
+
+        private void updateRoomPlaylist()
+            => playlist.Items.ReplaceRange(0, playlist.Items.Count, room.Playlist);
+
         protected override void OnTabChanged(BeatmapDetailAreaTabItem tab, bool selectedMods)
         {
             base.OnTabChanged(tab, selectedMods);
@@ -93,5 +100,11 @@ namespace osu.Game.Screens.OnlinePlay.Components
         }
 
         protected override BeatmapDetailAreaTabItem[] CreateTabItems() => base.CreateTabItems().Prepend(new BeatmapDetailAreaPlaylistTabItem()).ToArray();
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
+        }
     }
 }

osu.Game/Screens/OnlinePlay/Components/OnlinePlayBackgroundSprite.cs

@@ -1,41 +0,0 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-#nullable disable
-
-using osu.Framework.Allocation;
-using osu.Framework.Graphics;
-using osu.Game.Beatmaps.Drawables;
-using osu.Game.Online.Rooms;
-
-namespace osu.Game.Screens.OnlinePlay.Components
-{
-    public partial class OnlinePlayBackgroundSprite : OnlinePlayComposite
-    {
-        protected readonly BeatmapSetCoverType BeatmapSetCoverType;
-        private UpdateableBeatmapBackgroundSprite sprite;
-
-        public OnlinePlayBackgroundSprite(BeatmapSetCoverType beatmapSetCoverType = BeatmapSetCoverType.Cover)
-        {
-            BeatmapSetCoverType = beatmapSetCoverType;
-        }
-
-        [BackgroundDependencyLoader]
-        private void load()
-        {
-            InternalChild = sprite = CreateBackgroundSprite();
-
-            CurrentPlaylistItem.BindValueChanged(_ => updateBeatmap());
-            Playlist.CollectionChanged += (_, _) => updateBeatmap();
-
-            updateBeatmap();
-        }
-
-        private void updateBeatmap()
-        {
-            sprite.Beatmap.Value = CurrentPlaylistItem.Value?.Beatmap ?? Playlist.GetCurrentItem()?.Beatmap;
-        }
-
-        protected virtual UpdateableBeatmapBackgroundSprite CreateBackgroundSprite() => new UpdateableBeatmapBackgroundSprite(BeatmapSetCoverType) { RelativeSizeAxes = Axes.Both };
-    }
-}

osu.Game/Screens/OnlinePlay/Components/OverlinedHeader.cs

@@ -16,7 +16,7 @@ namespace osu.Game.Screens.OnlinePlay.Components
     /// <summary>
     /// A header used in the multiplayer interface which shows text / details beneath a line.
     /// </summary>
-    public partial class OverlinedHeader : OnlinePlayComposite
+    public partial class OverlinedHeader : CompositeDrawable
     {
         private bool showLine = true;
 

osu.Game/Screens/OnlinePlay/Components/OverlinedPlaylistHeader.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.ComponentModel;
 using osu.Framework.Allocation;
 using osu.Game.Online.Rooms;
 using osu.Game.Rulesets;
@@ -9,19 +10,38 @@ namespace osu.Game.Screens.OnlinePlay.Components
 {
     public partial class OverlinedPlaylistHeader : OverlinedHeader
     {
+        private readonly Room room;
+
         [Resolved]
         private RulesetStore rulesets { get; set; } = null!;
 
-        public OverlinedPlaylistHeader()
+        public OverlinedPlaylistHeader(Room room)
             : base("Playlist")
         {
+            this.room = room;
         }
 
         protected override void LoadComplete()
         {
             base.LoadComplete();
 
-            Playlist.BindCollectionChanged((_, _) => Details.Value = Playlist.GetTotalDuration(rulesets), true);
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateDuration();
+        }
+
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(Room.Playlist))
+                updateDuration();
+        }
+
+        private void updateDuration()
+            => Details.Value = room.Playlist.GetTotalDuration(rulesets);
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
         }
     }
 }

osu.Game/Screens/OnlinePlay/Components/ParticipantCountDisplay.cs

@@ -1,33 +1,36 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
+using System.ComponentModel;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
+using osu.Game.Online.Rooms;
 
 namespace osu.Game.Screens.OnlinePlay.Components
 {
-    public partial class ParticipantCountDisplay : OnlinePlayComposite
+    public partial class ParticipantCountDisplay : CompositeDrawable
     {
         private const float text_size = 30;
         private const float transition_duration = 100;
 
-        private OsuSpriteText slash, maxText;
+        private readonly Room room;
 
-        public ParticipantCountDisplay()
+        private OsuSpriteText slash = null!;
+        private OsuSpriteText maxText = null!;
+        private OsuSpriteText count = null!;
+
+        public ParticipantCountDisplay(Room room)
         {
+            this.room = room;
             AutoSizeAxes = Axes.Both;
         }
 
         [BackgroundDependencyLoader]
         private void load()
         {
-            OsuSpriteText count;
-
             InternalChild = new FillFlowContainer
             {
                 AutoSizeAxes = Axes.Both,
@@ -50,14 +53,33 @@ namespace osu.Game.Screens.OnlinePlay.Components
                     },
                 }
             };
-
-            MaxParticipants.BindValueChanged(_ => updateMax(), true);
-            ParticipantCount.BindValueChanged(c => count.Text = c.NewValue.ToString("#,0"), true);
         }
 
-        private void updateMax()
+        protected override void LoadComplete()
         {
-            if (MaxParticipants.Value == null)
+            base.LoadComplete();
+
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateRoomParticipantCount();
+        }
+
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            switch (e.PropertyName)
+            {
+                case nameof(Room.MaxParticipants):
+                    updateRoomMaxParticipants();
+                    break;
+
+                case nameof(Room.ParticipantCount):
+                    updateRoomParticipantCount();
+                    break;
+            }
+        }
+
+        private void updateRoomMaxParticipants()
+        {
+            if (room.MaxParticipants == null)
             {
                 slash.FadeOut(transition_duration);
                 maxText.FadeOut(transition_duration);
@@ -65,9 +87,18 @@ namespace osu.Game.Screens.OnlinePlay.Components
             else
             {
                 slash.FadeIn(transition_duration);
-                maxText.Text = MaxParticipants.Value.ToString();
+                maxText.Text = room.MaxParticipants.ToString()!;
                 maxText.FadeIn(transition_duration);
             }
         }
+
+        private void updateRoomParticipantCount()
+            => count.Text = room.ParticipantCount.ToString("#,0");
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
+        }
     }
 }

osu.Game/Screens/OnlinePlay/Components/ParticipantsDisplay.cs

@@ -1,25 +1,30 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using osu.Framework.Allocation;
+using System.ComponentModel;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
 using osu.Game.Graphics.Containers;
+using osu.Game.Online.Rooms;
 
 namespace osu.Game.Screens.OnlinePlay.Components
 {
-    public partial class ParticipantsDisplay : OnlinePlayComposite
+    public partial class ParticipantsDisplay : CompositeDrawable
     {
-        public Bindable<string> Details = new Bindable<string>();
+        public readonly Bindable<string> Details = new Bindable<string>();
 
-        public ParticipantsDisplay(Direction direction)
+        private readonly Room room;
+
+        public ParticipantsDisplay(Room room, Direction direction)
         {
+            this.room = room;
             OsuScrollContainer scroll;
             ParticipantsList list;
 
             AddInternal(scroll = new OsuScrollContainer(direction)
             {
-                Child = list = new ParticipantsList()
+                Child = list = new ParticipantsList(room)
             });
 
             switch (direction)
@@ -46,14 +51,32 @@ namespace osu.Game.Screens.OnlinePlay.Components
             }
         }
 
-        [BackgroundDependencyLoader]
-        private void load()
+        protected override void LoadComplete()
         {
-            ParticipantCount.BindValueChanged(_ => setParticipantCount());
-            MaxParticipants.BindValueChanged(_ => setParticipantCount(), true);
+            base.LoadComplete();
+
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateRoomParticipantCount();
         }
 
-        private void setParticipantCount() =>
-            Details.Value = MaxParticipants.Value != null ? $"{ParticipantCount.Value}/{MaxParticipants.Value}" : ParticipantCount.Value.ToString();
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            switch (e.PropertyName)
+            {
+                case nameof(Room.MaxParticipants):
+                case nameof(Room.ParticipantCount):
+                    updateRoomParticipantCount();
+                    break;
+            }
+        }
+
+        private void updateRoomParticipantCount()
+            => Details.Value = room.MaxParticipants != null ? $"{room.ParticipantCount}/{room.MaxParticipants}" : room.ParticipantCount.ToString();
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
+        }
     }
 }

osu.Game/Screens/OnlinePlay/Components/ParticipantsList.cs

@@ -1,21 +1,20 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
-using osu.Framework.Allocation;
+using System.ComponentModel;
 using osu.Framework.Extensions.Color4Extensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
 using osu.Framework.Threading;
 using osu.Game.Online.API.Requests.Responses;
+using osu.Game.Online.Rooms;
 using osu.Game.Users.Drawables;
 using osuTK;
 
 namespace osu.Game.Screens.OnlinePlay.Components
 {
-    public partial class ParticipantsList : OnlinePlayComposite
+    public partial class ParticipantsList : CompositeDrawable
     {
         public const float TILE_SIZE = 35;
 
@@ -57,15 +56,29 @@ namespace osu.Game.Screens.OnlinePlay.Components
             }
         }
 
-        [BackgroundDependencyLoader]
-        private void load()
+        private readonly Room room;
+
+        public ParticipantsList(Room room)
         {
-            RecentParticipants.CollectionChanged += (_, _) => updateParticipants();
+            this.room = room;
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            room.PropertyChanged += onRoomPropertyChanged;
             updateParticipants();
         }
 
-        private ScheduledDelegate scheduledUpdate;
-        private FillFlowContainer<UserTile> tiles;
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(Room.RecentParticipants))
+                updateParticipants();
+        }
+
+        private ScheduledDelegate? scheduledUpdate;
+        private FillFlowContainer<UserTile>? tiles;
 
         private void updateParticipants()
         {
@@ -83,8 +96,8 @@ namespace osu.Game.Screens.OnlinePlay.Components
                     Spacing = Vector2.One
                 };
 
-                for (int i = 0; i < RecentParticipants.Count; i++)
-                    tiles.Add(new UserTile { User = RecentParticipants[i] });
+                for (int i = 0; i < room.RecentParticipants.Count; i++)
+                    tiles.Add(new UserTile { User = room.RecentParticipants[i] });
 
                 AddInternal(tiles);
 
@@ -92,9 +105,15 @@ namespace osu.Game.Screens.OnlinePlay.Components
             });
         }
 
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
+        }
+
         private partial class UserTile : CompositeDrawable
         {
-            public APIUser User
+            public APIUser? User
             {
                 get => avatar.User;
                 set => avatar.User = value;

osu.Game/Screens/OnlinePlay/Components/RoomLocalUserInfo.cs

@@ -1,26 +1,28 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
+using System.ComponentModel;
 using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
+using osu.Game.Online.Rooms;
 
 namespace osu.Game.Screens.OnlinePlay.Components
 {
-    public partial class RoomLocalUserInfo : OnlinePlayComposite
+    public partial class RoomLocalUserInfo : CompositeDrawable
     {
-        private OsuSpriteText attemptDisplay;
+        private readonly Room room;
+        private OsuSpriteText attemptDisplay = null!;
 
         [Resolved]
-        private OsuColour colours { get; set; }
+        private OsuColour colours { get; set; } = null!;
 
-        public RoomLocalUserInfo()
+        public RoomLocalUserInfo(Room room)
         {
+            this.room = room;
             AutoSizeAxes = Axes.Both;
         }
 
@@ -45,19 +47,30 @@ namespace osu.Game.Screens.OnlinePlay.Components
         {
             base.LoadComplete();
 
-            MaxAttempts.BindValueChanged(_ => updateAttempts());
-            UserScore.BindValueChanged(_ => updateAttempts(), true);
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateAttempts();
+        }
+
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            switch (e.PropertyName)
+            {
+                case nameof(Room.UserScore):
+                case nameof(Room.MaxAttempts):
+                    updateAttempts();
+                    break;
+            }
         }
 
         private void updateAttempts()
         {
-            if (MaxAttempts.Value != null)
+            if (room.MaxAttempts != null)
             {
-                attemptDisplay.Text = $"Maximum attempts: {MaxAttempts.Value:N0}";
+                attemptDisplay.Text = $"Maximum attempts: {room.MaxAttempts:N0}";
 
-                if (UserScore.Value != null)
+                if (room.UserScore != null)
                 {
-                    int remaining = MaxAttempts.Value.Value - UserScore.Value.PlaylistItemAttempts.Sum(a => a.Attempts);
+                    int remaining = room.MaxAttempts.Value - room.UserScore.PlaylistItemAttempts.Sum(a => a.Attempts);
                     attemptDisplay.Text += $" ({remaining} remaining)";
 
                     if (remaining == 0)
@@ -69,5 +82,11 @@ namespace osu.Game.Screens.OnlinePlay.Components
                 attemptDisplay.Text = string.Empty;
             }
         }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
+        }
     }
 }

osu.Game/Screens/OnlinePlay/Components/RoomManager.cs

@@ -1,13 +1,10 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
-using JetBrains.Annotations;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Development;
@@ -20,18 +17,17 @@ namespace osu.Game.Screens.OnlinePlay.Components
 {
     public partial class RoomManager : Component, IRoomManager
     {
-        [CanBeNull]
-        public event Action RoomsUpdated;
+        public event Action? RoomsUpdated;
 
         private readonly BindableList<Room> rooms = new BindableList<Room>();
 
         public IBindableList<Room> Rooms => rooms;
 
-        protected IBindable<Room> JoinedRoom => joinedRoom;
-        private readonly Bindable<Room> joinedRoom = new Bindable<Room>();
+        protected IBindable<Room?> JoinedRoom => joinedRoom;
+        private readonly Bindable<Room?> joinedRoom = new Bindable<Room?>();
 
         [Resolved]
-        private IAPIProvider api { get; set; }
+        private IAPIProvider api { get; set; } = null!;
 
         public RoomManager()
         {
@@ -44,9 +40,9 @@ namespace osu.Game.Screens.OnlinePlay.Components
             PartRoom();
         }
 
-        public virtual void CreateRoom(Room room, Action<Room> onSuccess = null, Action<string> onError = null)
+        public virtual void CreateRoom(Room room, Action<Room>? onSuccess = null, Action<string>? onError = null)
         {
-            room.Host.Value = api.LocalUser.Value;
+            room.Host = api.LocalUser.Value;
 
             var req = new CreateRoomRequest(room);
 
@@ -69,9 +65,9 @@ namespace osu.Game.Screens.OnlinePlay.Components
             api.Queue(req);
         }
 
-        private JoinRoomRequest currentJoinRoomRequest;
+        private JoinRoomRequest? currentJoinRoomRequest;
 
-        public virtual void JoinRoom(Room room, string password = null, Action<Room> onSuccess = null, Action<string> onError = null)
+        public virtual void JoinRoom(Room room, string? password = null, Action<Room>? onSuccess = null, Action<string>? onError = null)
         {
             currentJoinRoomRequest?.Cancel();
             currentJoinRoomRequest = new JoinRoomRequest(room, password);
@@ -97,7 +93,7 @@ namespace osu.Game.Screens.OnlinePlay.Components
         {
             currentJoinRoomRequest?.Cancel();
 
-            if (JoinedRoom.Value == null)
+            if (joinedRoom.Value == null)
                 return;
 
             if (api.State.Value == APIState.Online)
@@ -111,14 +107,14 @@ namespace osu.Game.Screens.OnlinePlay.Components
         public void AddOrUpdateRoom(Room room)
         {
             Debug.Assert(ThreadSafety.IsUpdateThread);
-            Debug.Assert(room.RoomID.Value != null);
+            Debug.Assert(room.RoomID != null);
 
-            if (ignoredRooms.Contains(room.RoomID.Value.Value))
+            if (ignoredRooms.Contains(room.RoomID.Value))
                 return;
 
             try
             {
-                var existing = rooms.FirstOrDefault(e => e.RoomID.Value == room.RoomID.Value);
+                var existing = rooms.FirstOrDefault(e => e.RoomID == room.RoomID);
                 if (existing == null)
                     rooms.Add(room);
                 else
@@ -126,9 +122,9 @@ namespace osu.Game.Screens.OnlinePlay.Components
             }
             catch (Exception ex)
             {
-                Logger.Error(ex, $"Failed to update room: {room.Name.Value}.");
+                Logger.Error(ex, $"Failed to update room: {room.Name}.");
 
-                ignoredRooms.Add(room.RoomID.Value.Value);
+                ignoredRooms.Add(room.RoomID.Value);
                 rooms.Remove(room);
             }
 

osu.Game/Screens/OnlinePlay/Components/SelectionPollingComponent.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System.Threading.Tasks;
 using osu.Game.Online.Rooms;
 
@@ -20,21 +18,21 @@ namespace osu.Game.Screens.OnlinePlay.Components
             this.room = room;
         }
 
-        private GetRoomRequest lastPollRequest;
+        private GetRoomRequest? lastPollRequest;
 
         protected override Task Poll()
         {
             if (!API.IsLoggedIn)
                 return base.Poll();
 
-            if (room.RoomID.Value == null)
+            if (room.RoomID == null)
                 return base.Poll();
 
             var tcs = new TaskCompletionSource<bool>();
 
             lastPollRequest?.Cancel();
 
-            var req = new GetRoomRequest(room.RoomID.Value.Value);
+            var req = new GetRoomRequest(room.RoomID.Value);
 
             req.Success += result =>
             {

osu.Game/Screens/OnlinePlay/Components/StarRatingRangeDisplay.cs

@@ -1,9 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
+using System.ComponentModel;
 using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
@@ -13,22 +12,27 @@ using osu.Framework.Utils;
 using osu.Game.Beatmaps;
 using osu.Game.Beatmaps.Drawables;
 using osu.Game.Graphics;
+using osu.Game.Online.Rooms;
 using osuTK;
+using Container = osu.Framework.Graphics.Containers.Container;
 
 namespace osu.Game.Screens.OnlinePlay.Components
 {
-    public partial class StarRatingRangeDisplay : OnlinePlayComposite
+    public partial class StarRatingRangeDisplay : CompositeDrawable
     {
+        private readonly Room room;
+
         [Resolved]
-        private OsuColour colours { get; set; }
+        private OsuColour colours { get; set; } = null!;
 
-        private StarRatingDisplay minDisplay;
-        private Drawable minBackground;
-        private StarRatingDisplay maxDisplay;
-        private Drawable maxBackground;
+        private StarRatingDisplay minDisplay = null!;
+        private Drawable minBackground = null!;
+        private StarRatingDisplay maxDisplay = null!;
+        private Drawable maxBackground = null!;
 
-        public StarRatingRangeDisplay()
+        public StarRatingRangeDisplay(Room room)
         {
+            this.room = room;
             AutoSizeAxes = Axes.Both;
         }
 
@@ -76,8 +80,19 @@ namespace osu.Game.Screens.OnlinePlay.Components
         {
             base.LoadComplete();
 
-            DifficultyRange.BindValueChanged(_ => updateRange());
-            Playlist.BindCollectionChanged((_, _) => updateRange(), true);
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateRange();
+        }
+
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            switch (e.PropertyName)
+            {
+                case nameof(Room.Playlist):
+                case nameof(Room.DifficultyRange):
+                    updateRange();
+                    break;
+            }
         }
 
         private void updateRange()
@@ -85,16 +100,16 @@ namespace osu.Game.Screens.OnlinePlay.Components
             StarDifficulty minDifficulty;
             StarDifficulty maxDifficulty;
 
-            if (DifficultyRange.Value != null && Playlist.Count == 0)
+            if (room.DifficultyRange != null && room.Playlist.Count == 0)
             {
                 // When Playlist is empty (in lounge) we take retrieved range
-                minDifficulty = new StarDifficulty(DifficultyRange.Value.Min, 0);
-                maxDifficulty = new StarDifficulty(DifficultyRange.Value.Max, 0);
+                minDifficulty = new StarDifficulty(room.DifficultyRange.Min, 0);
+                maxDifficulty = new StarDifficulty(room.DifficultyRange.Max, 0);
             }
             else
             {
                 // When Playlist is not empty (in room) we compute actual range
-                var orderedDifficulties = Playlist.Select(p => p.Beatmap).OrderBy(b => b.StarRating).ToArray();
+                var orderedDifficulties = room.Playlist.Select(p => p.Beatmap).OrderBy(b => b.StarRating).ToArray();
 
                 minDifficulty = new StarDifficulty(orderedDifficulties.Length > 0 ? orderedDifficulties[0].StarRating : 0, 0);
                 maxDifficulty = new StarDifficulty(orderedDifficulties.Length > 0 ? orderedDifficulties[^1].StarRating : 0, 0);
@@ -107,5 +122,11 @@ namespace osu.Game.Screens.OnlinePlay.Components
             minBackground.Colour = colours.ForStarDifficulty(minDifficulty.Stars);
             maxBackground.Colour = colours.ForStarDifficulty(maxDifficulty.Stars);
         }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
+        }
     }
 }

osu.Game/Screens/OnlinePlay/Components/StatusColouredContainer.cs

@@ -1,39 +1,52 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
+using System.ComponentModel;
 using osu.Framework.Allocation;
-using osu.Framework.Bindables;
 using osu.Framework.Graphics;
-using osu.Framework.Graphics.Containers;
 using osu.Game.Graphics;
 using osu.Game.Online.Rooms;
+using Container = osu.Framework.Graphics.Containers.Container;
 
 namespace osu.Game.Screens.OnlinePlay.Components
 {
     public partial class StatusColouredContainer : Container
     {
+        [Resolved]
+        private OsuColour colours { get; set; } = null!;
+
         private readonly double transitionDuration;
+        private readonly Room room;
 
-        [Resolved(typeof(Room), nameof(Room.Status))]
-        private Bindable<RoomStatus> status { get; set; }
-
-        [Resolved(typeof(Room), nameof(Room.Category))]
-        private Bindable<RoomCategory> category { get; set; }
-
-        public StatusColouredContainer(double transitionDuration = 100)
+        public StatusColouredContainer(Room room, double transitionDuration = 100)
         {
+            this.room = room;
             this.transitionDuration = transitionDuration;
         }
 
-        [BackgroundDependencyLoader]
-        private void load(OsuColour colours)
+        protected override void LoadComplete()
         {
-            status.BindValueChanged(s =>
-            {
-                this.FadeColour(colours.ForRoomCategory(category.Value) ?? s.NewValue.GetAppropriateColour(colours), transitionDuration);
-            }, true);
+            base.LoadComplete();
+
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateRoomStatus();
+        }
+
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(Room.Status))
+                updateRoomStatus();
+        }
+
+        private void updateRoomStatus()
+        {
+            this.FadeColour(colours.ForRoomCategory(room.Category) ?? room.Status.GetAppropriateColour(colours), transitionDuration);
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
         }
     }
 }

osu.Game/Screens/OnlinePlay/DailyChallenge/DailyChallenge.cs

@@ -119,14 +119,6 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
             Padding = new MarginPadding { Horizontal = -HORIZONTAL_OVERFLOW_PADDING };
         }
 
-        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent)
-        {
-            return new CachedModelDependencyContainer<Room>(base.CreateChildDependencies(parent))
-            {
-                Model = { Value = room }
-            };
-        }
-
         [BackgroundDependencyLoader]
         private void load(AudioManager audio)
         {
@@ -228,7 +220,7 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
                                                                         Origin = Anchor.Centre,
                                                                         Children = new Drawable[]
                                                                         {
-                                                                            new DailyChallengeTimeRemainingRing(),
+                                                                            new DailyChallengeTimeRemainingRing(room),
                                                                             breakdown = new DailyChallengeScoreBreakdown(),
                                                                             totals = new DailyChallengeTotalsDisplay(),
                                                                         }
@@ -301,7 +293,7 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
                                                 Spacing = new Vector2(10),
                                                 Children = new Drawable[]
                                                 {
-                                                    new PlaylistsReadyButton
+                                                    new PlaylistsReadyButton(room)
                                                     {
                                                         Anchor = Anchor.Centre,
                                                         Origin = Anchor.Centre,
@@ -353,12 +345,12 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
         private void presentScore(long id)
         {
             if (this.IsCurrentScreen())
-                this.Push(new PlaylistItemScoreResultsScreen(room.RoomID.Value!.Value, playlistItem, id));
+                this.Push(new PlaylistItemScoreResultsScreen(room.RoomID!.Value, playlistItem, id));
         }
 
         private void onRoomScoreSet(MultiplayerRoomScoreSetEvent e)
         {
-            if (e.RoomID != room.RoomID.Value || e.PlaylistItemID != playlistItem.ID)
+            if (e.RoomID != room.RoomID || e.PlaylistItemID != playlistItem.ID)
                 return;
 
             userLookupCache.GetUserAsync(e.UserID).ContinueWith(t =>
@@ -410,7 +402,7 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
 
         private void dailyChallengeChanged(ValueChangedEvent<DailyChallengeInfo?> change)
         {
-            if (change.OldValue?.RoomID == room.RoomID.Value && change.NewValue == null && metadataClient.IsConnected.Value)
+            if (change.OldValue?.RoomID == room.RoomID && change.NewValue == null && metadataClient.IsConnected.Value)
             {
                 notificationOverlay?.Post(new SimpleNotification { Text = DailyChallengeStrings.ChallengeEndedNotification });
             }
@@ -437,7 +429,7 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
             roomManager.JoinRoom(room);
             startLoopingTrack(this, musicController);
 
-            metadataClient.BeginWatchingMultiplayerRoom(room.RoomID.Value!.Value).ContinueWith(t =>
+            metadataClient.BeginWatchingMultiplayerRoom(room.RoomID!.Value).ContinueWith(t =>
             {
                 if (t.Exception != null)
                 {
@@ -489,7 +481,7 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
             this.Delay(WaveContainer.DISAPPEAR_DURATION).FadeOut();
 
             roomManager.PartRoom();
-            metadataClient.EndWatchingMultiplayerRoom(room.RoomID.Value!.Value).FireAndForget();
+            metadataClient.EndWatchingMultiplayerRoom(room.RoomID!.Value).FireAndForget();
 
             return base.OnExiting(e);
         }

osu.Game/Screens/OnlinePlay/DailyChallenge/DailyChallengeIntro.cs

@@ -169,7 +169,7 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
                                         {
                                             Anchor = Anchor.Centre,
                                             Origin = Anchor.Centre,
-                                            Text = room.Name.Value.Split(':', StringSplitOptions.TrimEntries).Last(),
+                                            Text = room.Name.Split(':', StringSplitOptions.TrimEntries).Last(),
                                             Margin = new MarginPadding { Horizontal = 10f, Vertical = 5f },
                                             Shear = new Vector2(-OsuGame.SHEAR, 0f),
                                             Font = OsuFont.GetFont(size: 32, weight: FontWeight.Light, typeface: Typeface.TorusAlternate),

osu.Game/Screens/OnlinePlay/DailyChallenge/DailyChallengeLeaderboard.cs

@@ -138,7 +138,7 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
             if (request?.CompletionState == APIRequestCompletionState.Waiting)
                 return;
 
-            request = new IndexPlaylistScoresRequest(room.RoomID.Value!.Value, playlistItem.ID);
+            request = new IndexPlaylistScoresRequest(room.RoomID!.Value, playlistItem.ID);
 
             request.Success += req => Schedule(() =>
             {

osu.Game/Screens/OnlinePlay/DailyChallenge/DailyChallengeTimeRemainingRing.cs

@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using System.ComponentModel;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -10,15 +11,15 @@ using osu.Framework.Threading;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Graphics.UserInterface;
+using osu.Game.Online.Rooms;
 using osu.Game.Overlays;
 using osuTK;
 
 namespace osu.Game.Screens.OnlinePlay.DailyChallenge
 {
-    public partial class DailyChallengeTimeRemainingRing : OnlinePlayComposite
+    public partial class DailyChallengeTimeRemainingRing : CompositeDrawable
     {
-        private CircularProgress progress = null!;
-        private OsuSpriteText timeText = null!;
+        private readonly Room room;
 
         [Resolved]
         private OverlayColourProvider colourProvider { get; set; } = null!;
@@ -26,6 +27,14 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
         [Resolved]
         private OsuColour colours { get; set; } = null!;
 
+        private CircularProgress progress = null!;
+        private OsuSpriteText timeText = null!;
+
+        public DailyChallengeTimeRemainingRing(Room room)
+        {
+            this.room = room;
+        }
+
         [BackgroundDependencyLoader]
         private void load()
         {
@@ -90,12 +99,23 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
         {
             base.LoadComplete();
 
-            StartDate.BindValueChanged(_ => Scheduler.AddOnce(updateState));
-            EndDate.BindValueChanged(_ => Scheduler.AddOnce(updateState));
+            room.PropertyChanged += onRoomPropertyChanged;
             updateState();
+
             FinishTransforms(true);
         }
 
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            switch (e.PropertyName)
+            {
+                case nameof(Room.StartDate):
+                case nameof(Room.EndDate):
+                    Scheduler.AddOnce(updateState);
+                    break;
+            }
+        }
+
         private ScheduledDelegate? scheduledUpdate;
 
         private void updateState()
@@ -105,7 +125,7 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
 
             const float transition_duration = 300;
 
-            if (StartDate.Value == null || EndDate.Value == null || EndDate.Value < DateTimeOffset.Now)
+            if (room.StartDate == null || room.EndDate == null || room.EndDate < DateTimeOffset.Now)
             {
                 timeText.Text = TimeSpan.Zero.ToString(@"hh\:mm\:ss");
                 progress.Progress = 0;
@@ -114,8 +134,8 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
                 return;
             }
 
-            var roomDuration = EndDate.Value.Value - StartDate.Value.Value;
-            var remaining = EndDate.Value.Value - DateTimeOffset.Now;
+            var roomDuration = room.EndDate.Value - room.StartDate.Value;
+            var remaining = room.EndDate.Value - DateTimeOffset.Now;
 
             timeText.Text = remaining.ToString(@"hh\:mm\:ss");
             progress.Progress = remaining.TotalSeconds / roomDuration.TotalSeconds;
@@ -138,5 +158,11 @@ namespace osu.Game.Screens.OnlinePlay.DailyChallenge
 
             scheduledUpdate = Scheduler.AddDelayed(updateState, 1000);
         }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
+        }
     }
 }

osu.Game/Screens/OnlinePlay/Lounge/Components/DrawableRoom.cs

@@ -1,9 +1,9 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System.Collections.Generic;
+using System.ComponentModel;
+using System.Diagnostics;
 using System.Threading;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
@@ -16,6 +16,7 @@ using osu.Framework.Graphics.Effects;
 using osu.Framework.Graphics.Shapes;
 using osu.Framework.Graphics.Sprites;
 using osu.Game.Beatmaps;
+using osu.Game.Beatmaps.Drawables;
 using osu.Game.Database;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
@@ -26,30 +27,33 @@ using osu.Game.Overlays;
 using osu.Game.Screens.OnlinePlay.Components;
 using osuTK;
 using osuTK.Graphics;
+using Container = osu.Framework.Graphics.Containers.Container;
 
 namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 {
-    public partial class DrawableRoom : CompositeDrawable
+    public abstract partial class DrawableRoom : CompositeDrawable
     {
         protected const float CORNER_RADIUS = 10;
         private const float height = 100;
 
         public readonly Room Room;
 
-        protected Container ButtonsContainer { get; private set; }
+        protected readonly Bindable<PlaylistItem?> SelectedItem = new Bindable<PlaylistItem?>();
+        protected Container ButtonsContainer { get; private set; } = null!;
 
         private readonly Bindable<MatchType> roomType = new Bindable<MatchType>();
         private readonly Bindable<RoomCategory> roomCategory = new Bindable<RoomCategory>();
         private readonly Bindable<bool> hasPassword = new Bindable<bool>();
 
-        private DrawableRoomParticipantsList drawableRoomParticipantsList;
-        private RoomSpecialCategoryPill specialCategoryPill;
-        private PasswordProtectedIcon passwordIcon;
-        private EndDateInfo endDateInfo;
+        private DrawableRoomParticipantsList? drawableRoomParticipantsList;
+        private RoomSpecialCategoryPill? specialCategoryPill;
+        private PasswordProtectedIcon? passwordIcon;
+        private EndDateInfo? endDateInfo;
+        private SpriteText? roomName;
+        private UpdateableBeatmapBackgroundSprite background = null!;
+        private DelayedLoadWrapper wrapper = null!;
 
-        private DelayedLoadWrapper wrapper;
-
-        public DrawableRoom(Room room)
+        protected DrawableRoom(Room room)
         {
             Room = room;
 
@@ -77,7 +81,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
                 AutoSizeAxes = Axes.X
             };
 
-            InternalChildren = new[]
+            InternalChildren = new Drawable[]
             {
                 // This resolves internal 1px gaps due to applying the (parenting) corner radius and masking across multiple filling background sprites.
                 new Box
@@ -85,7 +89,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
                     RelativeSizeAxes = Axes.Both,
                     Colour = colours.Background5,
                 },
-                CreateBackground().With(d =>
+                background = CreateBackground().With(d =>
                 {
                     d.RelativeSizeAxes = Axes.Both;
                 }),
@@ -155,17 +159,17 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
                                                                 Spacing = new Vector2(5),
                                                                 Children = new Drawable[]
                                                                 {
-                                                                    new RoomStatusPill
+                                                                    new RoomStatusPill(Room)
                                                                     {
                                                                         Anchor = Anchor.CentreLeft,
                                                                         Origin = Anchor.CentreLeft
                                                                     },
-                                                                    specialCategoryPill = new RoomSpecialCategoryPill
+                                                                    specialCategoryPill = new RoomSpecialCategoryPill(Room)
                                                                     {
                                                                         Anchor = Anchor.CentreLeft,
                                                                         Origin = Anchor.CentreLeft
                                                                     },
-                                                                    endDateInfo = new EndDateInfo
+                                                                    endDateInfo = new EndDateInfo(Room)
                                                                     {
                                                                         Anchor = Anchor.CentreLeft,
                                                                         Origin = Anchor.CentreLeft,
@@ -180,13 +184,15 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
                                                                 Direction = FillDirection.Vertical,
                                                                 Children = new Drawable[]
                                                                 {
-                                                                    new TruncatingSpriteText
+                                                                    roomName = new TruncatingSpriteText
                                                                     {
                                                                         RelativeSizeAxes = Axes.X,
-                                                                        Font = OsuFont.GetFont(size: 28),
-                                                                        Current = { BindTarget = Room.Name }
+                                                                        Font = OsuFont.GetFont(size: 28)
                                                                     },
-                                                                    new RoomStatusText()
+                                                                    new RoomStatusText(Room)
+                                                                    {
+                                                                        SelectedItem = { BindTarget = SelectedItem }
+                                                                    }
                                                                 }
                                                             }
                                                         },
@@ -218,7 +224,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
                                                 Children = new Drawable[]
                                                 {
                                                     ButtonsContainer,
-                                                    drawableRoomParticipantsList = new DrawableRoomParticipantsList
+                                                    drawableRoomParticipantsList = new DrawableRoomParticipantsList(Room)
                                                     {
                                                         Anchor = Anchor.CentreRight,
                                                         Origin = Anchor.CentreRight,
@@ -243,36 +249,71 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
         {
             base.LoadComplete();
 
+            Room.PropertyChanged += onRoomPropertyChanged;
+
             wrapper.DelayedLoadComplete += _ =>
             {
+                Debug.Assert(specialCategoryPill != null);
+                Debug.Assert(endDateInfo != null);
+                Debug.Assert(passwordIcon != null);
+
                 wrapper.FadeInFromZero(200);
 
-                roomCategory.BindTo(Room.Category);
-                roomCategory.BindValueChanged(c =>
-                {
-                    if (c.NewValue > RoomCategory.Normal)
-                        specialCategoryPill.Show();
-                    else
-                        specialCategoryPill.Hide();
-                }, true);
-
-                roomType.BindTo(Room.Type);
-                roomType.BindValueChanged(t =>
-                {
-                    endDateInfo.Alpha = t.NewValue == MatchType.Playlists ? 1 : 0;
-                }, true);
-
-                hasPassword.BindTo(Room.HasPassword);
-                hasPassword.BindValueChanged(v => passwordIcon.Alpha = v.NewValue ? 1 : 0, true);
+                updateRoomName();
+                updateRoomCategory();
+                updateRoomType();
+                updateRoomHasPassword();
             };
+
+            SelectedItem.BindValueChanged(item => background.Beatmap.Value = item.NewValue?.Beatmap, true);
         }
 
-        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent)
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
         {
-            return new CachedModelDependencyContainer<Room>(base.CreateChildDependencies(parent))
+            switch (e.PropertyName)
             {
-                Model = { Value = Room }
-            };
+                case nameof(Room.Name):
+                    updateRoomName();
+                    break;
+
+                case nameof(Room.Category):
+                    updateRoomCategory();
+                    break;
+
+                case nameof(Room.Type):
+                    updateRoomType();
+                    break;
+
+                case nameof(Room.HasPassword):
+                    updateRoomHasPassword();
+                    break;
+            }
+        }
+
+        private void updateRoomName()
+        {
+            if (roomName != null)
+                roomName.Text = Room.Name;
+        }
+
+        private void updateRoomCategory()
+        {
+            if (Room.Category > RoomCategory.Normal)
+                specialCategoryPill?.Show();
+            else
+                specialCategoryPill?.Hide();
+        }
+
+        private void updateRoomType()
+        {
+            if (endDateInfo != null)
+                endDateInfo.Alpha = Room.Type == MatchType.Playlists ? 1 : 0;
+        }
+
+        private void updateRoomHasPassword()
+        {
+            if (passwordIcon != null)
+                passwordIcon.Alpha = Room.HasPassword ? 1 : 0;
         }
 
         private int numberOfAvatars = 7;
@@ -289,29 +330,29 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
             }
         }
 
-        protected virtual Drawable CreateBackground() => new OnlinePlayBackgroundSprite();
+        protected virtual UpdateableBeatmapBackgroundSprite CreateBackground() => new UpdateableBeatmapBackgroundSprite();
 
         protected virtual IEnumerable<Drawable> CreateBottomDetails()
         {
             var pills = new List<Drawable>();
 
-            if (Room.Type.Value != MatchType.Playlists)
+            if (Room.Type != MatchType.Playlists)
             {
-                pills.AddRange(new OnlinePlayComposite[]
+                pills.AddRange(new Drawable[]
                 {
-                    new MatchTypePill(),
-                    new QueueModePill(),
+                    new MatchTypePill(Room),
+                    new QueueModePill(Room),
                 });
             }
 
             pills.AddRange(new Drawable[]
             {
-                new PlaylistCountPill
+                new PlaylistCountPill(Room)
                 {
                     Anchor = Anchor.CentreLeft,
                     Origin = Anchor.CentreLeft,
                 },
-                new StarRatingRangeDisplay
+                new StarRatingRangeDisplay(Room)
                 {
                     Anchor = Anchor.CentreLeft,
                     Origin = Anchor.CentreLeft,
@@ -322,19 +363,29 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
             return pills;
         }
 
-        private partial class RoomStatusText : OnlinePlayComposite
+        protected override void Dispose(bool isDisposing)
         {
-            [Resolved]
-            private OsuColour colours { get; set; }
+            base.Dispose(isDisposing);
+            Room.PropertyChanged -= onRoomPropertyChanged;
+        }
+
+        private partial class RoomStatusText : CompositeDrawable
+        {
+            public readonly IBindable<PlaylistItem?> SelectedItem = new Bindable<PlaylistItem?>();
 
             [Resolved]
-            private BeatmapLookupCache beatmapLookupCache { get; set; }
+            private OsuColour colours { get; set; } = null!;
 
-            private SpriteText statusText;
-            private LinkFlowContainer beatmapText;
+            [Resolved]
+            private BeatmapLookupCache beatmapLookupCache { get; set; } = null!;
 
-            public RoomStatusText()
+            private readonly Room room;
+            private SpriteText statusText = null!;
+            private LinkFlowContainer beatmapText = null!;
+
+            public RoomStatusText(Room room)
             {
+                this.room = room;
                 RelativeSizeAxes = Axes.X;
                 AutoSizeAxes = Axes.Y;
             }
@@ -383,17 +434,17 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
             protected override void LoadComplete()
             {
                 base.LoadComplete();
-                CurrentPlaylistItem.BindValueChanged(onSelectedItemChanged, true);
+                SelectedItem.BindValueChanged(onSelectedItemChanged, true);
             }
 
-            private CancellationTokenSource beatmapLookupCancellation;
+            private CancellationTokenSource? beatmapLookupCancellation;
 
-            private void onSelectedItemChanged(ValueChangedEvent<PlaylistItem> item)
+            private void onSelectedItemChanged(ValueChangedEvent<PlaylistItem?> item)
             {
                 beatmapLookupCancellation?.Cancel();
                 beatmapText.Clear();
 
-                if (Type.Value == MatchType.Playlists)
+                if (room.Type == MatchType.Playlists)
                 {
                     statusText.Text = "Ready to play";
                     return;

osu.Game/Screens/OnlinePlay/Lounge/Components/DrawableRoomParticipantsList.cs

@@ -1,13 +1,10 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
-using System.Collections.Specialized;
-using System.Diagnostics;
+using System.Collections.Generic;
+using System.ComponentModel;
 using System.Linq;
 using osu.Framework.Allocation;
-using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
@@ -16,31 +13,33 @@ using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Online.API.Requests.Responses;
+using osu.Game.Online.Rooms;
 using osu.Game.Overlays;
 using osu.Game.Users.Drawables;
 using osuTK;
+using Container = osu.Framework.Graphics.Containers.Container;
 
 namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 {
-    public partial class DrawableRoomParticipantsList : OnlinePlayComposite
+    public partial class DrawableRoomParticipantsList : CompositeDrawable
     {
         public const float SHEAR_WIDTH = 12f;
-
         private const float avatar_size = 36;
-
         private const float height = 60f;
-
         private static readonly Vector2 shear = new Vector2(SHEAR_WIDTH / height, 0);
 
-        private FillFlowContainer<CircularAvatar> avatarFlow;
+        private readonly Room room;
 
-        private CircularAvatar hostAvatar;
-        private LinkFlowContainer hostText;
-        private HiddenUserCount hiddenUsers;
-        private OsuSpriteText totalCount;
+        private FillFlowContainer<CircularAvatar> avatarFlow = null!;
+        private CircularAvatar hostAvatar = null!;
+        private LinkFlowContainer hostText = null!;
+        private HiddenUserCount hiddenUsers = null!;
+        private OsuSpriteText totalCount = null!;
 
-        public DrawableRoomParticipantsList()
+        public DrawableRoomParticipantsList(Room room)
         {
+            this.room = room;
+
             AutoSizeAxes = Axes.X;
             Height = height;
         }
@@ -165,14 +164,11 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
         {
             base.LoadComplete();
 
-            RecentParticipants.BindCollectionChanged(onParticipantsChanged, true);
-            ParticipantCount.BindValueChanged(_ =>
-            {
-                updateHiddenUsers();
-                totalCount.Text = ParticipantCount.Value.ToString();
-            }, true);
+            room.PropertyChanged += onRoomPropertyChanged;
 
-            Host.BindValueChanged(onHostChanged, true);
+            updateRoomHost();
+            updateRoomParticipantCount();
+            updateRoomParticipants();
         }
 
         private int numberOfCircles = 4;
@@ -192,43 +188,38 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 
                 // Reinitialising the list looks janky, but this is unlikely to be used in a setting where it's visible.
                 clearUsers();
-                foreach (var u in RecentParticipants)
+                foreach (var u in room.RecentParticipants)
                     addUser(u);
 
                 updateHiddenUsers();
             }
         }
 
-        private void onParticipantsChanged(object sender, NotifyCollectionChangedEventArgs e)
+        private void updateRoomParticipants()
         {
-            switch (e.Action)
+            HashSet<APIUser> newUsers = room.RecentParticipants.ToHashSet();
+
+            avatarFlow.RemoveAll(a =>
             {
-                case NotifyCollectionChangedAction.Add:
-                    Debug.Assert(e.NewItems != null);
+                // Avatar with no user. Really shouldn't ever be the case but asserting it correctly is difficult.
+                if (a.User == null)
+                    return false;
 
-                    foreach (var added in e.NewItems.OfType<APIUser>())
-                        addUser(added);
-                    break;
+                // User was previously and still is a participant. Keep them around but remove them from the new set.
+                // This will be useful when we add all remaining users (now just the new participants) to the flow.
+                if (newUsers.Contains(a.User))
+                {
+                    newUsers.Remove(a.User);
+                    return false;
+                }
 
-                case NotifyCollectionChangedAction.Remove:
-                    Debug.Assert(e.OldItems != null);
+                // User is no longer a participant. Remove them from the flow.
+                return true;
+            }, true);
 
-                    foreach (var removed in e.OldItems.OfType<APIUser>())
-                        removeUser(removed);
-                    break;
-
-                case NotifyCollectionChangedAction.Reset:
-                    clearUsers();
-                    break;
-
-                case NotifyCollectionChangedAction.Replace:
-                case NotifyCollectionChangedAction.Move:
-                    // Easiest is to just reinitialise the whole list. These are unlikely to ever be use cases.
-                    clearUsers();
-                    foreach (var u in RecentParticipants)
-                        addUser(u);
-                    break;
-            }
+            // Add all remaining users to the flow.
+            foreach (var u in newUsers)
+                addUser(u);
 
             updateHiddenUsers();
         }
@@ -241,11 +232,6 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
                 avatarFlow.Add(new CircularAvatar { User = user });
         }
 
-        private void removeUser(APIUser user)
-        {
-            avatarFlow.RemoveAll(a => a.User == user, true);
-        }
-
         private void clearUsers()
         {
             avatarFlow.Clear();
@@ -255,8 +241,8 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
         private void updateHiddenUsers()
         {
             int hiddenCount = 0;
-            if (RecentParticipants.Count > NumberOfCircles)
-                hiddenCount = ParticipantCount.Value - NumberOfCircles + 1;
+            if (room.RecentParticipants.Count > NumberOfCircles)
+                hiddenCount = room.ParticipantCount - NumberOfCircles + 1;
 
             hiddenUsers.Count = hiddenCount;
 
@@ -264,26 +250,56 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
                 avatarFlow.Remove(avatarFlow.Last(), true);
             else if (displayedCircles < NumberOfCircles)
             {
-                var nextUser = RecentParticipants.FirstOrDefault(u => avatarFlow.All(a => a.User != u));
+                var nextUser = room.RecentParticipants.FirstOrDefault(u => avatarFlow.All(a => a.User != u));
                 if (nextUser != null) addUser(nextUser);
             }
         }
 
-        private void onHostChanged(ValueChangedEvent<APIUser> host)
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
         {
-            hostAvatar.User = host.NewValue;
+            switch (e.PropertyName)
+            {
+                case nameof(Room.Host):
+                    updateRoomHost();
+                    break;
+
+                case nameof(Room.ParticipantCount):
+                    updateRoomParticipantCount();
+                    break;
+
+                case nameof(Room.RecentParticipants):
+                    updateRoomParticipants();
+                    break;
+            }
+        }
+
+        private void updateRoomHost()
+        {
+            hostAvatar.User = room.Host;
             hostText.Clear();
 
-            if (host.NewValue != null)
+            if (room.Host != null)
             {
                 hostText.AddText("hosted by ");
-                hostText.AddUserLink(host.NewValue);
+                hostText.AddUserLink(room.Host);
             }
         }
 
+        private void updateRoomParticipantCount()
+        {
+            updateHiddenUsers();
+            totalCount.Text = room.ParticipantCount.ToString();
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
+        }
+
         private partial class CircularAvatar : CompositeDrawable
         {
-            public APIUser User
+            public APIUser? User
             {
                 get => avatar.User;
                 set => avatar.User = value;

osu.Game/Screens/OnlinePlay/Lounge/Components/EndDateInfo.cs

@@ -2,49 +2,69 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using System.ComponentModel;
 using osu.Framework.Allocation;
-using osu.Framework.Bindables;
 using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
 using osu.Game.Graphics;
+using osu.Game.Online.Rooms;
 
 namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 {
-    public partial class EndDateInfo : OnlinePlayComposite
+    public partial class EndDateInfo : CompositeDrawable
     {
-        public EndDateInfo()
+        private readonly Room room;
+
+        public EndDateInfo(Room room)
         {
+            this.room = room;
             AutoSizeAxes = Axes.Both;
         }
 
         [BackgroundDependencyLoader]
         private void load()
         {
-            InternalChild = new EndDatePart
+            InternalChild = new EndDatePart(room)
             {
                 Anchor = Anchor.CentreLeft,
                 Origin = Anchor.CentreLeft,
-                Font = OsuFont.GetFont(weight: FontWeight.SemiBold, size: 12),
-                EndDate = { BindTarget = EndDate }
+                Font = OsuFont.GetFont(weight: FontWeight.SemiBold, size: 12)
             };
         }
 
         private partial class EndDatePart : DrawableDate
         {
-            public readonly IBindable<DateTimeOffset?> EndDate = new Bindable<DateTimeOffset?>();
+            private readonly Room room;
 
-            public EndDatePart()
+            public EndDatePart(Room room)
                 : base(DateTimeOffset.UtcNow)
             {
-                EndDate.BindValueChanged(date =>
-                {
-                    // If null, set a very large future date to prevent unnecessary schedules.
-                    Date = date.NewValue ?? DateTimeOffset.Now.AddYears(1);
-                }, true);
+                this.room = room;
+            }
+
+            protected override void LoadComplete()
+            {
+                base.LoadComplete();
+
+                room.PropertyChanged += onRoomPropertyChanged;
+                updateEndDate();
+            }
+
+            private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+            {
+                if (e.PropertyName == nameof(Room.EndDate))
+                    updateEndDate();
+            }
+
+            private void updateEndDate()
+            {
+                // If null, set a very large future date to prevent unnecessary schedules.
+                Date = room.EndDate ?? DateTimeOffset.Now.AddYears(1);
             }
 
             protected override string Format()
             {
-                if (EndDate.Value == null)
+                if (room.EndDate == null)
                     return string.Empty;
 
                 var diffToNow = Date.Subtract(DateTimeOffset.Now);
@@ -60,6 +80,12 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 
                 return $"Closing {base.Format()}";
             }
+
+            protected override void Dispose(bool isDisposing)
+            {
+                base.Dispose(isDisposing);
+                room.PropertyChanged -= onRoomPropertyChanged;
+            }
         }
     }
 }

osu.Game/Screens/OnlinePlay/Lounge/Components/MatchTypePill.cs

@@ -1,7 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using osu.Framework.Bindables;
+using System.ComponentModel;
 using osu.Framework.Extensions;
 using osu.Game.Online.Rooms;
 
@@ -9,16 +9,36 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 {
     public partial class MatchTypePill : OnlinePlayPill
     {
+        private readonly Room room;
+
+        public MatchTypePill(Room room)
+        {
+            this.room = room;
+        }
+
         protected override void LoadComplete()
         {
             base.LoadComplete();
 
-            Type.BindValueChanged(onMatchTypeChanged, true);
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateRoomType();
         }
 
-        private void onMatchTypeChanged(ValueChangedEvent<MatchType> type)
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
         {
-            TextFlow.Text = type.NewValue.GetLocalisableDescription();
+            if (e.PropertyName == nameof(Room.Type))
+                updateRoomType();
+        }
+
+        private void updateRoomType()
+        {
+            TextFlow.Text = room.Type.GetLocalisableDescription();
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
         }
     }
 }

osu.Game/Screens/OnlinePlay/Lounge/Components/OnlinePlayPill.cs

@@ -3,13 +3,14 @@
 
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Sprites;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
 
 namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 {
-    public abstract partial class OnlinePlayPill : OnlinePlayComposite
+    public abstract partial class OnlinePlayPill : CompositeDrawable
     {
         protected PillContainer Pill { get; private set; } = null!;
         protected OsuTextFlowContainer TextFlow { get; private set; } = null!;

osu.Game/Screens/OnlinePlay/Lounge/Components/PlaylistCountPill.cs

@@ -1,10 +1,12 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.ComponentModel;
 using System.Linq;
 using Humanizer;
 using osu.Framework.Extensions.LocalisationExtensions;
 using osu.Game.Graphics;
+using osu.Game.Online.Rooms;
 
 namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 {
@@ -13,26 +15,50 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
     /// </summary>
     public partial class PlaylistCountPill : OnlinePlayPill
     {
+        private readonly Room room;
+
+        public PlaylistCountPill(Room room)
+        {
+            this.room = room;
+        }
+
         protected override void LoadComplete()
         {
             base.LoadComplete();
 
-            PlaylistItemStats.BindValueChanged(_ => updateCount());
-            Playlist.BindCollectionChanged((_, _) => updateCount(), true);
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateCount();
+        }
+
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            switch (e.PropertyName)
+            {
+                case nameof(Room.Playlist):
+                case nameof(Room.PlaylistItemStats):
+                    updateCount();
+                    break;
+            }
         }
 
         private void updateCount()
         {
-            int activeItems = Playlist.Count > 0 || PlaylistItemStats.Value == null
+            int activeItems = room.Playlist.Count > 0 || room.PlaylistItemStats == null
                 // For now, use the playlist as the source of truth if it has any items.
                 // This allows the count to display correctly on the room screen (after joining a room).
-                ? Playlist.Count(i => !i.Expired)
-                : PlaylistItemStats.Value.CountActive;
+                ? room.Playlist.Count(i => !i.Expired)
+                : room.PlaylistItemStats.CountActive;
 
             TextFlow.Clear();
             TextFlow.AddText(activeItems.ToLocalisableString(), s => s.Font = s.Font.With(weight: FontWeight.Bold));
             TextFlow.AddText(" ");
             TextFlow.AddText("Beatmap".ToQuantity(activeItems, ShowQuantityAs.None));
         }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
+        }
     }
 }

osu.Game/Screens/OnlinePlay/Lounge/Components/QueueModePill.cs

@@ -1,24 +1,42 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using osu.Framework.Bindables;
+using System.ComponentModel;
 using osu.Framework.Extensions;
-using osu.Game.Online.Multiplayer;
+using osu.Game.Online.Rooms;
 
 namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 {
     public partial class QueueModePill : OnlinePlayPill
     {
+        private readonly Room room;
+
+        public QueueModePill(Room room)
+        {
+            this.room = room;
+        }
+
         protected override void LoadComplete()
         {
             base.LoadComplete();
 
-            QueueMode.BindValueChanged(onQueueModeChanged, true);
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateRoomQueueMode();
         }
 
-        private void onQueueModeChanged(ValueChangedEvent<QueueMode> mode)
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
         {
-            TextFlow.Text = mode.NewValue.GetLocalisableDescription();
+            if (e.PropertyName == nameof(Room.QueueMode))
+                updateRoomQueueMode();
+        }
+
+        private void updateRoomQueueMode()
+            => TextFlow.Text = room.QueueMode.GetLocalisableDescription();
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
         }
     }
 }

osu.Game/Screens/OnlinePlay/Lounge/Components/RoomSpecialCategoryPill.cs

@@ -1,21 +1,30 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.ComponentModel;
 using osu.Framework.Allocation;
 using osu.Framework.Extensions;
 using osu.Framework.Graphics.Sprites;
 using osu.Game.Graphics;
+using osu.Game.Online.Rooms;
 using osuTK.Graphics;
 
 namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 {
     public partial class RoomSpecialCategoryPill : OnlinePlayPill
     {
+        private readonly Room room;
+
         [Resolved]
         private OsuColour colours { get; set; } = null!;
 
         protected override FontUsage Font => base.Font.With(weight: FontWeight.SemiBold);
 
+        public RoomSpecialCategoryPill(Room room)
+        {
+            this.room = room;
+        }
+
         protected override void LoadComplete()
         {
             base.LoadComplete();
@@ -23,11 +32,26 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
             Pill.Background.Alpha = 1;
             TextFlow.Colour = Color4.Black;
 
-            Category.BindValueChanged(c =>
-            {
-                TextFlow.Text = c.NewValue.GetLocalisableDescription();
-                Pill.Background.Colour = colours.ForRoomCategory(c.NewValue) ?? colours.Pink;
-            }, true);
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateRoomCategory();
+        }
+
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(Room.Category))
+                updateRoomCategory();
+        }
+
+        private void updateRoomCategory()
+        {
+            TextFlow.Text = room.Category.GetLocalisableDescription();
+            Pill.Background.Colour = colours.ForRoomCategory(room.Category) ?? colours.Pink;
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
         }
     }
 }

osu.Game/Screens/OnlinePlay/Lounge/Components/RoomStatusPill.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.ComponentModel;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Sprites;
@@ -19,25 +20,47 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 
         protected override FontUsage Font => base.Font.With(weight: FontWeight.SemiBold);
 
+        private readonly Room room;
+
+        public RoomStatusPill(Room room)
+        {
+            this.room = room;
+        }
+
         protected override void LoadComplete()
         {
             base.LoadComplete();
 
-            EndDate.BindValueChanged(_ => updateDisplay());
-            Status.BindValueChanged(_ => updateDisplay(), true);
-
-            FinishTransforms(true);
-
             TextFlow.Colour = Colour4.Black;
             Pill.Background.Alpha = 1;
+
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateDisplay();
+
+            FinishTransforms(true);
+        }
+
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            switch (e.PropertyName)
+            {
+                case nameof(Room.Status):
+                case nameof(Room.EndDate):
+                    updateDisplay();
+                    break;
+            }
         }
 
         private void updateDisplay()
         {
-            RoomStatus status = Status.Value;
+            Pill.Background.FadeColour(room.Status.GetAppropriateColour(colours), 100);
+            TextFlow.Text = room.Status.Message;
+        }
 
-            Pill.Background.FadeColour(status.GetAppropriateColour(colours), 100);
-            TextFlow.Text = status.Message;
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
         }
     }
 }

osu.Game/Screens/OnlinePlay/Lounge/Components/RoomsContainer.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using System.Collections.Specialized;
@@ -11,6 +9,7 @@ using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Extensions.IEnumerableExtensions;
+using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Input.Bindings;
@@ -24,8 +23,8 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 {
     public partial class RoomsContainer : CompositeDrawable, IKeyBindingHandler<GlobalAction>
     {
-        public readonly Bindable<Room> SelectedRoom = new Bindable<Room>();
-        public readonly Bindable<FilterCriteria> Filter = new Bindable<FilterCriteria>();
+        public readonly Bindable<Room?> SelectedRoom = new Bindable<Room?>();
+        public readonly Bindable<FilterCriteria?> Filter = new Bindable<FilterCriteria?>();
 
         public IReadOnlyList<DrawableRoom> Rooms => roomFlow.FlowingChildren.Cast<DrawableRoom>().ToArray();
 
@@ -33,7 +32,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
         private readonly FillFlowContainer<DrawableLoungeRoom> roomFlow;
 
         [Resolved]
-        private IRoomManager roomManager { get; set; }
+        private IRoomManager roomManager { get; set; } = null!;
 
         // handle deselection
         public override bool ReceivePositionalInputAt(Vector2 screenSpacePos) => true;
@@ -67,10 +66,10 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 
             rooms.BindTo(roomManager.Rooms);
 
-            Filter?.BindValueChanged(criteria => applyFilterCriteria(criteria.NewValue), true);
+            Filter.BindValueChanged(criteria => applyFilterCriteria(criteria.NewValue), true);
         }
 
-        private void applyFilterCriteria(FilterCriteria criteria)
+        private void applyFilterCriteria(FilterCriteria? criteria)
         {
             roomFlow.Children.ForEach(r =>
             {
@@ -80,7 +79,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
                 {
                     bool matchingFilter = true;
 
-                    matchingFilter &= criteria.Ruleset == null || r.Room.PlaylistItemStats.Value?.RulesetIDs.Any(id => id == criteria.Ruleset.OnlineID) != false;
+                    matchingFilter &= criteria.Ruleset == null || r.Room.PlaylistItemStats?.RulesetIDs.Any(id => id == criteria.Ruleset.OnlineID) != false;
 
                     if (!string.IsNullOrEmpty(criteria.SearchString))
                     {
@@ -102,10 +101,10 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
                         return true;
 
                     case RoomPermissionsFilter.Public:
-                        return !room.Room.HasPassword.Value;
+                        return !room.Room.HasPassword;
 
                     case RoomPermissionsFilter.Private:
-                        return room.Room.HasPassword.Value;
+                        return room.Room.HasPassword;
 
                     default:
                         throw new ArgumentOutOfRangeException(nameof(accessType), accessType, $"Unsupported {nameof(RoomPermissionsFilter)} in filter");
@@ -113,7 +112,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
             }
         }
 
-        private void roomsChanged(object sender, NotifyCollectionChangedEventArgs args)
+        private void roomsChanged(object? sender, NotifyCollectionChangedEventArgs args)
         {
             switch (args.Action)
             {
@@ -140,9 +139,9 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
         private void addRooms(IEnumerable<Room> rooms)
         {
             foreach (var room in rooms)
-                roomFlow.Add(new DrawableLoungeRoom(room) { SelectedRoom = { BindTarget = SelectedRoom } });
+                roomFlow.Add(new DrawableLoungeRoom(room) { SelectedRoom = SelectedRoom });
 
-            applyFilterCriteria(Filter?.Value);
+            applyFilterCriteria(Filter.Value);
         }
 
         private void removeRooms(IEnumerable<Room> rooms)
@@ -170,10 +169,10 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
         {
             foreach (var room in roomFlow)
             {
-                roomFlow.SetLayoutPosition(room, room.Room.Category.Value > RoomCategory.Normal
+                roomFlow.SetLayoutPosition(room, room.Room.Category > RoomCategory.Normal
                     // Always show spotlight playlists at the top of the listing.
                     ? float.MinValue
-                    : -(room.Room.RoomID.Value ?? 0));
+                    : -(room.Room.RoomID ?? 0));
             }
         }
 
@@ -213,7 +212,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
 
             var visibleRooms = Rooms.AsEnumerable().Where(r => r.IsPresent);
 
-            Room room;
+            Room? room;
 
             if (SelectedRoom.Value == null)
                 room = visibleRooms.FirstOrDefault()?.Room;
@@ -236,7 +235,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge.Components
         {
             base.Dispose(isDisposing);
 
-            if (roomManager != null)
+            if (roomManager.IsNotNull())
                 roomManager.RoomsUpdated -= updateSorting;
         }
     }

osu.Game/Screens/OnlinePlay/Lounge/DrawableLoungeRoom.cs

@@ -1,9 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System.Collections.Generic;
+using System.ComponentModel;
 using osu.Framework.Allocation;
 using osu.Framework.Audio;
 using osu.Framework.Audio.Sample;
@@ -28,6 +27,7 @@ using osu.Game.Screens.OnlinePlay.Components;
 using osu.Game.Screens.OnlinePlay.Lounge.Components;
 using osuTK;
 using osuTK.Graphics;
+using Container = osu.Framework.Graphics.Containers.Container;
 
 namespace osu.Game.Screens.OnlinePlay.Lounge
 {
@@ -39,14 +39,19 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
         private const float transition_duration = 60;
         private const float selection_border_width = 4;
 
-        public readonly Bindable<Room> SelectedRoom = new Bindable<Room>();
+        public required Bindable<Room?> SelectedRoom
+        {
+            get => selectedRoom;
+            set => selectedRoom.Current = value;
+        }
 
         [Resolved(canBeNull: true)]
-        private LoungeSubScreen lounge { get; set; }
+        private LoungeSubScreen? lounge { get; set; }
 
-        private Sample sampleSelect;
-        private Sample sampleJoin;
-        private Drawable selectionBox;
+        private readonly BindableWithCurrent<Room?> selectedRoom = new BindableWithCurrent<Room?>();
+        private Sample? sampleSelect;
+        private Sample? sampleJoin;
+        private Drawable selectionBox = null!;
 
         public DrawableLoungeRoom(Room room)
             : base(room)
@@ -61,7 +66,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
 
             AddRangeInternal(new Drawable[]
             {
-                new StatusColouredContainer(transition_duration)
+                new StatusColouredContainer(Room, transition_duration)
                 {
                     RelativeSizeAxes = Axes.Both,
                     Child = selectionBox = new Container
@@ -89,12 +94,24 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
             base.LoadComplete();
 
             Alpha = matchingFilter ? 1 : 0;
-            selectionBox.Alpha = SelectedRoom.Value == Room ? 1 : 0;
+            selectionBox.Alpha = selectedRoom.Value == Room ? 1 : 0;
 
-            SelectedRoom.BindValueChanged(updateSelectedRoom);
+            selectedRoom.BindValueChanged(updateSelectedRoom);
+
+            Room.PropertyChanged += onRoomPropertyChanged;
+            updateSelectedItem();
         }
 
-        private void updateSelectedRoom(ValueChangedEvent<Room> selected)
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(Room.CurrentPlaylistItem))
+                updateSelectedItem();
+        }
+
+        private void updateSelectedItem()
+            => SelectedItem.Value = Room.CurrentPlaylistItem;
+
+        private void updateSelectedRoom(ValueChangedEvent<Room?> selected)
         {
             if (selected.NewValue == Room)
                 selectionBox.FadeIn(transition_duration);
@@ -104,7 +121,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
 
         public bool FilteringActive { get; set; }
 
-        public IEnumerable<LocalisableString> FilterTerms => new LocalisableString[] { Room.Name.Value };
+        public IEnumerable<LocalisableString> FilterTerms => new LocalisableString[] { Room.Name };
 
         private bool matchingFilter = true;
 
@@ -140,7 +157,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
             if (e.Repeat)
                 return false;
 
-            if (SelectedRoom.Value != Room)
+            if (selectedRoom.Value != Room)
                 return false;
 
             switch (e.Action)
@@ -157,18 +174,18 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
         {
         }
 
-        protected override bool ShouldBeConsideredForInput(Drawable child) => SelectedRoom.Value == Room || child is HoverSounds;
+        protected override bool ShouldBeConsideredForInput(Drawable child) => selectedRoom.Value == Room || child is HoverSounds;
 
         protected override bool OnClick(ClickEvent e)
         {
-            if (Room != SelectedRoom.Value)
+            if (Room != selectedRoom.Value)
             {
                 sampleSelect?.Play();
-                SelectedRoom.Value = Room;
+                selectedRoom.Value = Room;
                 return true;
             }
 
-            if (Room.HasPassword.Value)
+            if (Room.HasPassword)
             {
                 this.ShowPopover();
                 return true;
@@ -179,12 +196,18 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
             return true;
         }
 
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            Room.PropertyChanged -= onRoomPropertyChanged;
+        }
+
         public partial class PasswordEntryPopover : OsuPopover
         {
             private readonly Room room;
 
             [Resolved(canBeNull: true)]
-            private LoungeSubScreen lounge { get; set; }
+            private LoungeSubScreen? lounge { get; set; }
 
             public override bool HandleNonPositionalInput => true;
 
@@ -195,10 +218,10 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
                 this.room = room;
             }
 
-            private OsuPasswordTextBox passwordTextBox;
-            private RoundedButton joinButton;
-            private OsuSpriteText errorText;
-            private Sample sampleJoinFail;
+            private OsuPasswordTextBox passwordTextBox = null!;
+            private RoundedButton joinButton = null!;
+            private OsuSpriteText errorText = null!;
+            private Sample? sampleJoinFail;
 
             [BackgroundDependencyLoader]
             private void load(OsuColour colours, AudioManager audio)

osu.Game/Screens/OnlinePlay/Lounge/LoungeBackgroundScreen.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.ComponentModel;
 using osu.Framework.Bindables;
 using osu.Framework.Screens;
 using osu.Game.Online.Rooms;
@@ -19,21 +20,44 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
             playlist.BindCollectionChanged((_, _) => PlaylistItem = playlist.GetCurrentItem());
         }
 
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+            SelectedRoom.BindValueChanged(onSelectedRoomChanged, true);
+        }
+
         private void onSelectedRoomChanged(ValueChangedEvent<Room?> room)
         {
             if (room.OldValue != null)
-                playlist.UnbindFrom(room.OldValue.Playlist);
+                room.OldValue.PropertyChanged -= onRoomPropertyChanged;
 
             if (room.NewValue != null)
-                playlist.BindTo(room.NewValue.Playlist);
-            else
-                playlist.Clear();
+                room.NewValue.PropertyChanged += onRoomPropertyChanged;
+
+            updateCurrentItem();
         }
 
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(Room.Playlist))
+                updateCurrentItem();
+        }
+
+        private void updateCurrentItem()
+            => PlaylistItem = SelectedRoom.Value?.Playlist.GetCurrentItem();
+
         public override bool OnExiting(ScreenExitEvent e)
         {
             // This screen never exits.
             return true;
         }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+
+            if (SelectedRoom.Value != null)
+                SelectedRoom.Value.PropertyChanged -= onRoomPropertyChanged;
+        }
     }
 }

osu.Game/Screens/OnlinePlay/Lounge/LoungeSubScreen.cs

@@ -259,7 +259,7 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
             selectionLease.Return();
             selectionLease = null;
 
-            if (SelectedRoom.Value?.RoomID.Value == null)
+            if (SelectedRoom.Value?.RoomID == null)
                 SelectedRoom.Value = new Room();
 
             music?.EnsurePlayingSomething();
@@ -326,23 +326,23 @@ namespace osu.Game.Screens.OnlinePlay.Lounge
         /// <param name="room">The room to copy.</param>
         public void OpenCopy(Room room)
         {
-            Debug.Assert(room.RoomID.Value != null);
+            Debug.Assert(room.RoomID != null);
 
             if (joiningRoomOperation != null)
                 return;
 
             joiningRoomOperation = ongoingOperationTracker?.BeginOperation();
 
-            var req = new GetRoomRequest(room.RoomID.Value.Value);
+            var req = new GetRoomRequest(room.RoomID.Value);
 
             req.Success += r =>
             {
                 // ID must be unset as we use this as a marker for whether this is a client-side (not-yet-created) room or not.
-                r.RoomID.Value = null;
+                r.RoomID = null;
 
                 // Null out dates because end date is not supported client-side and the settings overlay will populate a duration.
-                r.EndDate.Value = null;
-                r.Duration.Value = null;
+                r.EndDate = null;
+                r.Duration = null;
 
                 Open(r);
 

osu.Game/Screens/OnlinePlay/Match/Components/MatchChatDisplay.cs

@@ -1,8 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.ComponentModel;
 using osu.Framework.Allocation;
-using osu.Framework.Bindables;
 using osu.Game.Online.Chat;
 using osu.Game.Online.Rooms;
 
@@ -10,8 +10,6 @@ namespace osu.Game.Screens.OnlinePlay.Match.Components
 {
     public partial class MatchChatDisplay : StandAloneChatDisplay
     {
-        private readonly IBindable<int> channelId = new Bindable<int>();
-
         [Resolved]
         private ChannelManager? channelManager { get; set; }
 
@@ -29,23 +27,30 @@ namespace osu.Game.Screens.OnlinePlay.Match.Components
         {
             base.LoadComplete();
 
-            // Required for the time being since this component is created prior to the room being joined.
-            channelId.BindTo(room.ChannelId);
-            channelId.BindValueChanged(_ => updateChannel(), true);
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateChannel();
+        }
+
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(Room.ChannelId))
+                updateChannel();
         }
 
         private void updateChannel()
         {
-            if (room.RoomID.Value == null || channelId.Value == 0)
+            if (room.RoomID == null || room.ChannelId == 0)
                 return;
 
-            Channel.Value = channelManager?.JoinChannel(new Channel { Id = channelId.Value, Type = ChannelType.Multiplayer, Name = $"#lazermp_{room.RoomID.Value}" });
+            Channel.Value = channelManager?.JoinChannel(new Channel { Id = room.ChannelId, Type = ChannelType.Multiplayer, Name = $"#lazermp_{room.RoomID.Value}" });
         }
 
         protected override void Dispose(bool isDisposing)
         {
             base.Dispose(isDisposing);
 
+            room.PropertyChanged -= onRoomPropertyChanged;
+
             if (leaveChannelOnDispose)
                 channelManager?.LeaveChannel(Channel.Value);
         }

osu.Game/Screens/OnlinePlay/Match/Components/MatchLeaderboard.cs

@@ -1,9 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.ComponentModel;
 using System.Threading;
-using osu.Framework.Allocation;
-using osu.Framework.Bindables;
 using osu.Game.Online.API;
 using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Online.Leaderboards;
@@ -13,30 +12,44 @@ namespace osu.Game.Screens.OnlinePlay.Match.Components
 {
     public partial class MatchLeaderboard : Leaderboard<MatchLeaderboardScope, APIUserScoreAggregate>
     {
-        [Resolved(typeof(Room), nameof(Room.RoomID))]
-        private Bindable<long?> roomId { get; set; } = null!;
+        private readonly Room room;
 
-        [BackgroundDependencyLoader]
-        private void load()
+        public MatchLeaderboard(Room room)
         {
-            roomId.BindValueChanged(id =>
-            {
-                if (id.NewValue == null)
-                    return;
+            this.room = room;
+        }
 
-                SetScores(null);
-                RefetchScores();
-            }, true);
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            room.PropertyChanged += onRoomPropertyChanged;
+            fetchInitialScores();
+        }
+
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(Room.RoomID))
+                fetchInitialScores();
+        }
+
+        private void fetchInitialScores()
+        {
+            if (room.RoomID == null)
+                return;
+
+            SetScores(null);
+            RefetchScores();
         }
 
         protected override bool IsOnlineScope => true;
 
         protected override APIRequest? FetchScores(CancellationToken cancellationToken)
         {
-            if (roomId.Value == null)
+            if (room.RoomID == null)
                 return null;
 
-            var req = new GetRoomLeaderboardRequest(roomId.Value ?? 0);
+            var req = new GetRoomLeaderboardRequest(room.RoomID.Value);
 
             req.Success += r => Schedule(() =>
             {
@@ -52,6 +65,12 @@ namespace osu.Game.Screens.OnlinePlay.Match.Components
         protected override LeaderboardScore CreateDrawableScore(APIUserScoreAggregate model, int index) => new MatchLeaderboardScore(model, index);
 
         protected override LeaderboardScore CreateDrawableTopScore(APIUserScoreAggregate model) => new MatchLeaderboardScore(model, model.Position, false);
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
+        }
     }
 
     public enum MatchLeaderboardScope

osu.Game/Screens/OnlinePlay/Match/Components/RoomSettingsOverlay.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -23,7 +21,7 @@ namespace osu.Game.Screens.OnlinePlay.Match.Components
         protected const float TRANSITION_DURATION = 350;
         protected const float FIELD_PADDING = 25;
 
-        protected OnlinePlayComposite Settings { get; set; }
+        protected Drawable Settings { get; set; } = null!;
 
         protected override bool BlockScrollInput => false;
 
@@ -50,7 +48,7 @@ namespace osu.Game.Screens.OnlinePlay.Match.Components
 
         protected abstract void SelectBeatmap();
 
-        protected abstract OnlinePlayComposite CreateSettings(Room room);
+        protected abstract Drawable CreateSettings(Room room);
 
         protected override void PopIn()
         {

osu.Game/Screens/OnlinePlay/Match/DrawableMatchRoom.cs

@@ -1,16 +1,13 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
-using JetBrains.Annotations;
+using System.ComponentModel;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Game.Beatmaps.Drawables;
 using osu.Game.Online.API;
-using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Online.Rooms;
 using osu.Game.Resources.Localisation.Web;
 using osu.Game.Screens.OnlinePlay.Lounge.Components;
@@ -21,26 +18,27 @@ namespace osu.Game.Screens.OnlinePlay.Match
 {
     public partial class DrawableMatchRoom : DrawableRoom
     {
-        public readonly IBindable<PlaylistItem> SelectedItem = new Bindable<PlaylistItem>();
-        public Action OnEdit;
+        public Action? OnEdit;
+
+        public new required Bindable<PlaylistItem?> SelectedItem
+        {
+            get => selectedItem;
+            set => selectedItem.Current = value;
+        }
 
         [Resolved]
-        private IAPIProvider api { get; set; }
+        private IAPIProvider api { get; set; } = null!;
 
-        private readonly IBindable<APIUser> host = new Bindable<APIUser>();
+        private readonly BindableWithCurrent<PlaylistItem?> selectedItem = new BindableWithCurrent<PlaylistItem?>();
         private readonly bool allowEdit;
-
-        [CanBeNull]
-        private Drawable editButton;
-
-        private BackgroundSprite background;
+        private Drawable? editButton;
 
         public DrawableMatchRoom(Room room, bool allowEdit = true)
             : base(room)
         {
             this.allowEdit = allowEdit;
 
-            host.BindTo(room.Host);
+            base.SelectedItem.BindTo(SelectedItem);
         }
 
         [BackgroundDependencyLoader]
@@ -62,17 +60,31 @@ namespace osu.Game.Screens.OnlinePlay.Match
         {
             base.LoadComplete();
 
-            if (editButton != null)
-                host.BindValueChanged(h => editButton.Alpha = h.NewValue?.Equals(api.LocalUser.Value) == true ? 1 : 0, true);
-
-            SelectedItem.BindValueChanged(item => background.Beatmap.Value = item.NewValue?.Beatmap, true);
+            Room.PropertyChanged += onRoomPropertyChanged;
+            updateRoomHost();
         }
 
-        protected override Drawable CreateBackground() => background = new BackgroundSprite();
-
-        private partial class BackgroundSprite : UpdateableBeatmapBackgroundSprite
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
         {
-            protected override double LoadDelay => 0;
+            if (e.PropertyName == nameof(Room.Host))
+                updateRoomHost();
+        }
+
+        private void updateRoomHost()
+        {
+            if (editButton != null)
+                editButton.Alpha = Room.Host?.Equals(api.LocalUser.Value) == true ? 1 : 0;
+        }
+
+        protected override UpdateableBeatmapBackgroundSprite CreateBackground() => base.CreateBackground().With(d =>
+        {
+            d.BackgroundLoadDelay = 0;
+        });
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            Room.PropertyChanged -= onRoomPropertyChanged;
         }
     }
 }

osu.Game/Screens/OnlinePlay/Match/RoomSubScreen.cs

@@ -5,6 +5,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Diagnostics;
 using System.Linq;
 using JetBrains.Annotations;
@@ -29,13 +30,13 @@ using osu.Game.Rulesets.Mods;
 using osu.Game.Screens.Menu;
 using osu.Game.Screens.OnlinePlay.Match.Components;
 using osu.Game.Screens.OnlinePlay.Multiplayer;
+using Container = osu.Framework.Graphics.Containers.Container;
 
 namespace osu.Game.Screens.OnlinePlay.Match
 {
     [Cached(typeof(IPreviewTrackOwner))]
     public abstract partial class RoomSubScreen : OnlinePlaySubScreen, IPreviewTrackOwner
     {
-        [Cached(typeof(IBindable<PlaylistItem>))]
         public readonly Bindable<PlaylistItem> SelectedItem = new Bindable<PlaylistItem>();
 
         public override bool? ApplyModTrackAdjustments => true;
@@ -60,8 +61,6 @@ namespace osu.Game.Screens.OnlinePlay.Match
         /// </summary>
         protected readonly Bindable<IReadOnlyList<Mod>> UserMods = new Bindable<IReadOnlyList<Mod>>(Array.Empty<Mod>());
 
-        protected readonly IBindable<long?> RoomId = new Bindable<long?>();
-
         [Resolved(CanBeNull = true)]
         private IOverlayManager overlayManager { get; set; }
 
@@ -83,6 +82,9 @@ namespace osu.Game.Screens.OnlinePlay.Match
         [Resolved]
         private PreviewTrackManager previewTrackManager { get; set; } = null!;
 
+        [Resolved(canBeNull: true)]
+        private IDialogOverlay dialogOverlay { get; set; }
+
         [Cached]
         private readonly OnlinePlayBeatmapAvailabilityTracker beatmapAvailabilityTracker = new OnlinePlayBeatmapAvailabilityTracker();
 
@@ -110,8 +112,6 @@ namespace osu.Game.Screens.OnlinePlay.Match
             this.allowEdit = allowEdit;
 
             Padding = new MarginPadding { Top = Header.HEIGHT };
-
-            RoomId.BindTo(room.RoomID);
         }
 
         [BackgroundDependencyLoader]
@@ -164,7 +164,7 @@ namespace osu.Game.Screens.OnlinePlay.Match
                                                     new DrawableMatchRoom(Room, allowEdit)
                                                     {
                                                         OnEdit = () => settingsOverlay.Show(),
-                                                        SelectedItem = { BindTarget = SelectedItem }
+                                                        SelectedItem = SelectedItem
                                                     }
                                                 },
                                                 null,
@@ -253,22 +253,6 @@ namespace osu.Game.Screens.OnlinePlay.Match
         {
             base.LoadComplete();
 
-            RoomId.BindValueChanged(id =>
-            {
-                if (id.NewValue == null)
-                {
-                    // A new room is being created.
-                    // The main content should be hidden until the settings overlay is hidden, signaling the room is ready to be displayed.
-                    mainContent.Hide();
-                    settingsOverlay.Show();
-                }
-                else
-                {
-                    mainContent.Show();
-                    settingsOverlay.Hide();
-                }
-            }, true);
-
             SelectedItem.BindValueChanged(_ => Scheduler.AddOnce(selectedItemChanged));
             UserMods.BindValueChanged(_ => Scheduler.AddOnce(UpdateMods));
 
@@ -276,24 +260,38 @@ namespace osu.Game.Screens.OnlinePlay.Match
             beatmapAvailabilityTracker.Availability.BindValueChanged(_ => updateWorkingBeatmap());
 
             userModsSelectOverlayRegistration = overlayManager?.RegisterBlockingOverlay(UserModsSelectOverlay);
+
+            Room.PropertyChanged += onRoomPropertyChanged;
+            updateSetupState();
         }
 
-        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent)
+        private void onRoomPropertyChanged(object sender, PropertyChangedEventArgs e)
         {
-            return new CachedModelDependencyContainer<Room>(base.CreateChildDependencies(parent))
-            {
-                Model = { Value = Room }
-            };
+            if (e.PropertyName == nameof(Room.RoomID))
+                updateSetupState();
         }
 
-        [Resolved(canBeNull: true)]
-        private IDialogOverlay dialogOverlay { get; set; }
+        private void updateSetupState()
+        {
+            if (Room.RoomID == null)
+            {
+                // A new room is being created.
+                // The main content should be hidden until the settings overlay is hidden, signaling the room is ready to be displayed.
+                mainContent.Hide();
+                settingsOverlay.Show();
+            }
+            else
+            {
+                mainContent.Show();
+                settingsOverlay.Hide();
+            }
+        }
 
         protected virtual bool IsConnected => api.State.Value == APIState.Online;
 
         public override bool OnBackButton()
         {
-            if (Room.RoomID.Value == null)
+            if (Room.RoomID == null)
             {
                 if (!ensureExitConfirmed())
                     return true;
@@ -366,7 +364,7 @@ namespace osu.Game.Screens.OnlinePlay.Match
             if (!IsConnected)
                 return true;
 
-            bool hasUnsavedChanges = Room.RoomID.Value == null && Room.Playlist.Count > 0;
+            bool hasUnsavedChanges = Room.RoomID == null && Room.Playlist.Count > 0;
 
             if (dialogOverlay == null || !hasUnsavedChanges)
                 return true;
@@ -539,6 +537,7 @@ namespace osu.Game.Screens.OnlinePlay.Match
             base.Dispose(isDisposing);
 
             userModsSelectOverlayRegistration?.Dispose();
+            Room.PropertyChanged -= onRoomPropertyChanged;
         }
     }
 }

osu.Game/Screens/OnlinePlay/Multiplayer/Match/MatchStartControl.cs

@@ -23,6 +23,12 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
 {
     public partial class MatchStartControl : CompositeDrawable
     {
+        public required Bindable<PlaylistItem?> SelectedItem
+        {
+            get => selectedItem;
+            set => selectedItem.Current = value;
+        }
+
         [Resolved]
         private OngoingOperationTracker ongoingOperationTracker { get; set; } = null!;
 
@@ -32,9 +38,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
         [Resolved]
         private MultiplayerClient client { get; set; } = null!;
 
-        [Resolved]
-        private IBindable<PlaylistItem?> currentItem { get; set; } = null!;
-
+        private readonly BindableWithCurrent<PlaylistItem?> selectedItem = new BindableWithCurrent<PlaylistItem?>();
         private readonly MultiplayerReadyButton readyButton;
         private readonly MultiplayerCountdownButton countdownButton;
 
@@ -94,7 +98,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
         {
             base.LoadComplete();
 
-            currentItem.BindValueChanged(_ => updateState());
+            SelectedItem.BindValueChanged(_ => updateState());
             client.RoomUpdated += onRoomUpdated;
             client.LoadRequested += onLoadRequested;
             updateState();
@@ -210,7 +214,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
 
             readyButton.Enabled.Value = countdownButton.Enabled.Value =
                 client.Room.State != MultiplayerRoomState.Closed
-                && currentItem.Value?.ID == client.Room.Settings.PlaylistItemId
+                && SelectedItem.Value?.ID == client.Room.Settings.PlaylistItemId
                 && !client.Room.Playlist.Single(i => i.ID == client.Room.Settings.PlaylistItemId).Expired
                 && !operationInProgress.Value;
 

osu.Game/Screens/OnlinePlay/Multiplayer/Match/MultiplayerMatchFooter.cs

@@ -1,10 +1,10 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
+using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
+using osu.Game.Online.Rooms;
 
 namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
 {
@@ -13,6 +13,14 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
         private const float ready_button_width = 600;
         private const float spectate_button_width = 200;
 
+        public required Bindable<PlaylistItem?> SelectedItem
+        {
+            get => selectedItem;
+            set => selectedItem.Current = value;
+        }
+
+        private readonly BindableWithCurrent<PlaylistItem?> selectedItem = new BindableWithCurrent<PlaylistItem?>();
+
         public MultiplayerMatchFooter()
         {
             RelativeSizeAxes = Axes.Both;
@@ -22,17 +30,19 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
                 RelativeSizeAxes = Axes.Both,
                 Content = new[]
                 {
-                    new Drawable[]
+                    new Drawable?[]
                     {
                         null,
                         new MultiplayerSpectateButton
                         {
                             RelativeSizeAxes = Axes.Both,
+                            SelectedItem = selectedItem
                         },
                         null,
                         new MatchStartControl
                         {
                             RelativeSizeAxes = Axes.Both,
+                            SelectedItem = selectedItem
                         },
                         null
                     }

osu.Game/Screens/OnlinePlay/Multiplayer/Match/MultiplayerMatchSettingsOverlay.cs

@@ -4,6 +4,7 @@
 using System;
 using System.ComponentModel;
 using System.Diagnostics;
+using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Extensions;
@@ -28,14 +29,20 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
 {
     public partial class MultiplayerMatchSettingsOverlay : RoomSettingsOverlay
     {
-        private MatchSettings settings = null!;
+        public required Bindable<PlaylistItem?> SelectedItem
+        {
+            get => selectedItem;
+            set => selectedItem.Current = value;
+        }
 
         protected override OsuButton SubmitButton => settings.ApplyButton;
+        protected override bool IsLoading => ongoingOperationTracker.InProgress.Value;
 
         [Resolved]
         private OngoingOperationTracker ongoingOperationTracker { get; set; } = null!;
 
-        protected override bool IsLoading => ongoingOperationTracker.InProgress.Value;
+        private readonly BindableWithCurrent<PlaylistItem?> selectedItem = new BindableWithCurrent<PlaylistItem?>();
+        private MatchSettings settings = null!;
 
         public MultiplayerMatchSettingsOverlay(Room room)
             : base(room)
@@ -44,19 +51,21 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
 
         protected override void SelectBeatmap() => settings.SelectBeatmap();
 
-        protected override OnlinePlayComposite CreateSettings(Room room) => settings = new MatchSettings(room)
+        protected override Drawable CreateSettings(Room room) => settings = new MatchSettings(room)
         {
             RelativeSizeAxes = Axes.Both,
             RelativePositionAxes = Axes.Y,
-            SettingsApplied = Hide
+            SettingsApplied = Hide,
+            SelectedItem = { BindTarget = SelectedItem }
         };
 
-        protected partial class MatchSettings : OnlinePlayComposite
+        protected partial class MatchSettings : CompositeDrawable
         {
             private const float disabled_alpha = 0.2f;
 
             public override bool IsPresent => base.IsPresent || Scheduler.HasPendingTasks;
 
+            public readonly Bindable<PlaylistItem?> SelectedItem = new Bindable<PlaylistItem?>();
             public Action? SettingsApplied;
 
             public OsuTextBox NameField = null!;
@@ -66,7 +75,6 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
             public OsuTextBox PasswordTextBox = null!;
             public OsuCheckbox AutoSkipCheckbox = null!;
             public RoundedButton ApplyButton = null!;
-
             public OsuSpriteText ErrorText = null!;
 
             private OsuEnumDropdown<StartMode> startModeDropdown = null!;
@@ -270,7 +278,8 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
                                                         drawablePlaylist = new DrawableRoomPlaylist
                                                         {
                                                             RelativeSizeAxes = Axes.X,
-                                                            Height = DrawableRoomPlaylistItem.HEIGHT
+                                                            Height = DrawableRoomPlaylistItem.HEIGHT,
+                                                            SelectedItem = { BindTarget = SelectedItem }
                                                         },
                                                         selectBeatmapButton = new RoundedButton
                                                         {
@@ -316,7 +325,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
                                             Padding = new MarginPadding { Horizontal = OsuScreen.HORIZONTAL_OVERFLOW_PADDING },
                                             Children = new Drawable[]
                                             {
-                                                ApplyButton = new CreateOrUpdateButton
+                                                ApplyButton = new CreateOrUpdateButton(room)
                                                 {
                                                     Anchor = Anchor.BottomCentre,
                                                     Origin = Anchor.BottomCentre,
@@ -343,14 +352,6 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
                 };
 
                 TypePicker.Current.BindValueChanged(type => typeLabel.Text = type.NewValue.GetLocalisableDescription(), true);
-                RoomName.BindValueChanged(name => NameField.Text = name.NewValue, true);
-                Type.BindValueChanged(type => TypePicker.Current.Value = type.NewValue, true);
-                MaxParticipants.BindValueChanged(count => MaxParticipantsField.Text = count.NewValue?.ToString(), true);
-                RoomID.BindValueChanged(roomId => playlistContainer.Alpha = roomId.NewValue == null ? 1 : 0, true);
-                Password.BindValueChanged(password => PasswordTextBox.Text = password.NewValue ?? string.Empty, true);
-                QueueMode.BindValueChanged(mode => QueueModeDropdown.Current.Value = mode.NewValue, true);
-                AutoStartDuration.BindValueChanged(duration => startModeDropdown.Current.Value = (StartMode)(int)duration.NewValue.TotalSeconds, true);
-                AutoSkip.BindValueChanged(autoSkip => AutoSkipCheckbox.Current.Value = autoSkip.NewValue, true);
 
                 operationInProgress.BindTo(ongoingOperationTracker.InProgress);
                 operationInProgress.BindValueChanged(v =>
@@ -366,15 +367,88 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
             {
                 base.LoadComplete();
 
-                drawablePlaylist.Items.BindTo(Playlist);
-                drawablePlaylist.SelectedItem.BindTo(CurrentPlaylistItem);
+                room.PropertyChanged += onRoomPropertyChanged;
+
+                updateRoomName();
+                updateRoomType();
+                updateRoomQueueMode();
+                updateRoomPassword();
+                updateRoomAutoSkip();
+                updateRoomMaxParticipants();
+                updateRoomAutoStartDuration();
+                updateRoomPlaylist();
+
+                drawablePlaylist.Items.BindCollectionChanged((_, __) => room.Playlist = drawablePlaylist.Items.ToArray());
             }
 
+            private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+            {
+                switch (e.PropertyName)
+                {
+                    case nameof(Room.Name):
+                        updateRoomName();
+                        break;
+
+                    case nameof(Room.Type):
+                        updateRoomName();
+                        break;
+
+                    case nameof(Room.QueueMode):
+                        updateRoomQueueMode();
+                        break;
+
+                    case nameof(Room.Password):
+                        updateRoomPassword();
+                        break;
+
+                    case nameof(Room.AutoSkip):
+                        updateRoomAutoSkip();
+                        break;
+
+                    case nameof(Room.MaxParticipants):
+                        updateRoomMaxParticipants();
+                        break;
+
+                    case nameof(Room.AutoStartDuration):
+                        updateRoomAutoStartDuration();
+                        break;
+
+                    case nameof(Room.Playlist):
+                        updateRoomPlaylist();
+                        break;
+                }
+            }
+
+            private void updateRoomName()
+                => NameField.Text = room.Name;
+
+            private void updateRoomType()
+                => TypePicker.Current.Value = room.Type;
+
+            private void updateRoomQueueMode()
+                => QueueModeDropdown.Current.Value = room.QueueMode;
+
+            private void updateRoomPassword()
+                => PasswordTextBox.Text = room.Password ?? string.Empty;
+
+            private void updateRoomAutoSkip()
+                => AutoSkipCheckbox.Current.Value = room.AutoSkip;
+
+            private void updateRoomMaxParticipants()
+                => MaxParticipantsField.Text = room.MaxParticipants?.ToString();
+
+            private void updateRoomAutoStartDuration()
+                => typeLabel.Text = room.AutoStartDuration.GetLocalisableDescription();
+
+            private void updateRoomPlaylist()
+                => drawablePlaylist.Items.ReplaceRange(0, drawablePlaylist.Items.Count, room.Playlist);
+
             protected override void Update()
             {
                 base.Update();
 
-                ApplyButton.Enabled.Value = Playlist.Count > 0 && NameField.Text.Length > 0 && !operationInProgress.Value;
+                ApplyButton.Enabled.Value = room.Playlist.Count > 0 && NameField.Text.Length > 0 && !operationInProgress.Value;
+                playlistContainer.Alpha = room.RoomID == null ? 1 : 0;
             }
 
             private void apply()
@@ -387,8 +461,6 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
                 Debug.Assert(applyingSettingsOperation == null);
                 applyingSettingsOperation = ongoingOperationTracker.BeginOperation();
 
-                TimeSpan autoStartDuration = TimeSpan.FromSeconds((int)startModeDropdown.Current.Value);
-
                 // If the client is already in a room, update via the client.
                 // Otherwise, update the room directly in preparation for it to be submitted to the API on match creation.
                 if (client.Room != null)
@@ -398,7 +470,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
                               password: PasswordTextBox.Text,
                               matchType: TypePicker.Current.Value,
                               queueMode: QueueModeDropdown.Current.Value,
-                              autoStartDuration: autoStartDuration,
+                              autoStartDuration: TimeSpan.FromSeconds((int)startModeDropdown.Current.Value),
                               autoSkip: AutoSkipCheckbox.Current.Value)
                           .ContinueWith(t => Schedule(() =>
                           {
@@ -410,17 +482,17 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
                 }
                 else
                 {
-                    room.Name.Value = NameField.Text;
-                    room.Type.Value = TypePicker.Current.Value;
-                    room.Password.Value = PasswordTextBox.Current.Value;
-                    room.QueueMode.Value = QueueModeDropdown.Current.Value;
-                    room.AutoStartDuration.Value = autoStartDuration;
-                    room.AutoSkip.Value = AutoSkipCheckbox.Current.Value;
+                    room.Name = NameField.Text;
+                    room.Type = TypePicker.Current.Value;
+                    room.Password = PasswordTextBox.Current.Value;
+                    room.QueueMode = QueueModeDropdown.Current.Value;
+                    room.AutoStartDuration = TimeSpan.FromSeconds((int)startModeDropdown.Current.Value);
+                    room.AutoSkip = AutoSkipCheckbox.Current.Value;
 
                     if (int.TryParse(MaxParticipantsField.Text, out int max))
-                        room.MaxParticipants.Value = max;
+                        room.MaxParticipants = max;
                     else
-                        room.MaxParticipants.Value = null;
+                        room.MaxParticipants = null;
 
                     manager.CreateRoom(room, onSuccess, onError);
                 }
@@ -448,7 +520,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
                 if (text.StartsWith(not_found_prefix, StringComparison.Ordinal))
                 {
                     ErrorText.Text = "The selected beatmap is not available online.";
-                    CurrentPlaylistItem.Value.MarkInvalid();
+                    SelectedItem.Value?.MarkInvalid();
                 }
                 else
                 {
@@ -460,17 +532,21 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
                 applyingSettingsOperation.Dispose();
                 applyingSettingsOperation = null;
             });
+
+            protected override void Dispose(bool isDisposing)
+            {
+                base.Dispose(isDisposing);
+                room.PropertyChanged -= onRoomPropertyChanged;
+            }
         }
 
         public partial class CreateOrUpdateButton : RoundedButton
         {
-            [Resolved(typeof(Room), nameof(Room.RoomID))]
-            private Bindable<long?> roomId { get; set; } = null!;
+            private readonly Room room;
 
-            protected override void LoadComplete()
+            public CreateOrUpdateButton(Room room)
             {
-                base.LoadComplete();
-                roomId.BindValueChanged(id => Text = id.NewValue == null ? "Create" : "Update", true);
+                this.room = room;
             }
 
             [BackgroundDependencyLoader]
@@ -478,6 +554,13 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
             {
                 BackgroundColour = colours.YellowDark;
             }
+
+            protected override void Update()
+            {
+                base.Update();
+
+                Text = room.RoomID == null ? "Create" : "Update";
+            }
         }
 
         private enum StartMode

osu.Game/Screens/OnlinePlay/Multiplayer/Match/MultiplayerSpectateButton.cs

@@ -21,6 +21,12 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
 {
     public partial class MultiplayerSpectateButton : CompositeDrawable
     {
+        public required Bindable<PlaylistItem?> SelectedItem
+        {
+            get => selectedItem;
+            set => selectedItem.Current = value;
+        }
+
         [Resolved]
         private OngoingOperationTracker ongoingOperationTracker { get; set; } = null!;
 
@@ -30,13 +36,11 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
         [Resolved]
         private MultiplayerClient client { get; set; } = null!;
 
-        [Resolved]
-        private IBindable<PlaylistItem?> currentItem { get; set; } = null!;
+        private readonly BindableWithCurrent<PlaylistItem?> selectedItem = new BindableWithCurrent<PlaylistItem?>();
+        private readonly RoundedButton button;
 
         private IBindable<bool> operationInProgress = null!;
 
-        private readonly RoundedButton button;
-
         public MultiplayerSpectateButton()
         {
             InternalChild = button = new RoundedButton
@@ -71,7 +75,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
         {
             base.LoadComplete();
 
-            currentItem.BindValueChanged(_ => Scheduler.AddOnce(checkForAutomaticDownload), true);
+            SelectedItem.BindValueChanged(_ => Scheduler.AddOnce(checkForAutomaticDownload), true);
             client.RoomUpdated += onRoomUpdated;
             updateState();
         }
@@ -117,7 +121,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
 
         private void checkForAutomaticDownload()
         {
-            PlaylistItem? item = currentItem.Value;
+            PlaylistItem? item = SelectedItem.Value;
 
             downloadCheckCancellation?.Cancel();
 

osu.Game/Screens/OnlinePlay/Multiplayer/Match/Playlist/MultiplayerPlaylist.cs

@@ -19,6 +19,12 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match.Playlist
     {
         public readonly Bindable<MultiplayerPlaylistDisplayMode> DisplayMode = new Bindable<MultiplayerPlaylistDisplayMode>();
 
+        public required Bindable<PlaylistItem?> SelectedItem
+        {
+            get => selectedItem;
+            set => selectedItem.Current = value;
+        }
+
         /// <summary>
         /// Invoked when an item requests to be edited.
         /// </summary>
@@ -27,14 +33,18 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match.Playlist
         [Resolved]
         private MultiplayerClient client { get; set; } = null!;
 
-        [Resolved]
-        private IBindable<PlaylistItem?> currentItem { get; set; } = null!;
-
+        private readonly Room room;
+        private readonly BindableWithCurrent<PlaylistItem?> selectedItem = new BindableWithCurrent<PlaylistItem?>();
         private MultiplayerPlaylistTabControl playlistTabControl = null!;
         private MultiplayerQueueList queueList = null!;
         private MultiplayerHistoryList historyList = null!;
         private bool firstPopulation = true;
 
+        public MultiplayerPlaylist(Room room)
+        {
+            this.room = room;
+        }
+
         [BackgroundDependencyLoader]
         private void load()
         {
@@ -55,17 +65,17 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match.Playlist
                     Masking = true,
                     Children = new Drawable[]
                     {
-                        queueList = new MultiplayerQueueList
+                        queueList = new MultiplayerQueueList(room)
                         {
                             RelativeSizeAxes = Axes.Both,
-                            SelectedItem = { BindTarget = currentItem },
+                            SelectedItem = { BindTarget = selectedItem },
                             RequestEdit = item => RequestEdit?.Invoke(item)
                         },
                         historyList = new MultiplayerHistoryList
                         {
                             RelativeSizeAxes = Axes.Both,
                             Alpha = 0,
-                            SelectedItem = { BindTarget = currentItem }
+                            SelectedItem = { BindTarget = selectedItem }
                         }
                     }
                 }

osu.Game/Screens/OnlinePlay/Multiplayer/Match/Playlist/MultiplayerQueueList.cs

@@ -1,12 +1,11 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Linq;
 using osu.Framework.Allocation;
-using osu.Framework.Bindables;
+using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Game.Online.API;
@@ -21,28 +20,49 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match.Playlist
     /// </summary>
     public partial class MultiplayerQueueList : DrawableRoomPlaylist
     {
-        public MultiplayerQueueList()
+        private readonly Room room;
+
+        private QueueFillFlowContainer flow = null!;
+
+        public MultiplayerQueueList(Room room)
         {
+            this.room = room;
             ShowItemOwners = true;
         }
 
-        protected override FillFlowContainer<RearrangeableListItem<PlaylistItem>> CreateListFillFlowContainer() => new QueueFillFlowContainer
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateRoomPlaylist();
+        }
+
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(Room.Playlist))
+                updateRoomPlaylist();
+        }
+
+        private void updateRoomPlaylist()
+            => flow.InvalidateLayout();
+
+        protected override FillFlowContainer<RearrangeableListItem<PlaylistItem>> CreateListFillFlowContainer() => flow = new QueueFillFlowContainer
         {
             Spacing = new Vector2(0, 2)
         };
 
         protected override DrawableRoomPlaylistItem CreateDrawablePlaylistItem(PlaylistItem item) => new QueuePlaylistItem(item);
 
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
+        }
+
         private partial class QueueFillFlowContainer : FillFlowContainer<RearrangeableListItem<PlaylistItem>>
         {
-            [Resolved(typeof(Room), nameof(Room.Playlist))]
-            private BindableList<PlaylistItem> roomPlaylist { get; set; }
-
-            protected override void LoadComplete()
-            {
-                base.LoadComplete();
-                roomPlaylist.BindCollectionChanged((_, _) => InvalidateLayout());
-            }
+            public new void InvalidateLayout() => base.InvalidateLayout();
 
             public override IEnumerable<Drawable> FlowingChildren => base.FlowingChildren.OfType<RearrangeableListItem<PlaylistItem>>().OrderBy(item => item.Model.PlaylistOrder);
         }
@@ -50,10 +70,10 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match.Playlist
         private partial class QueuePlaylistItem : DrawableRoomPlaylistItem
         {
             [Resolved]
-            private IAPIProvider api { get; set; }
+            private IAPIProvider api { get; set; } = null!;
 
             [Resolved]
-            private MultiplayerClient multiplayerClient { get; set; }
+            private MultiplayerClient multiplayerClient { get; set; } = null!;
 
             public QueuePlaylistItem(PlaylistItem item)
                 : base(item)
@@ -91,7 +111,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match.Playlist
             {
                 base.Dispose(isDisposing);
 
-                if (multiplayerClient != null)
+                if (multiplayerClient.IsNotNull())
                     multiplayerClient.RoomUpdated -= onRoomUpdated;
             }
         }

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerLoungeSubScreen.cs

@@ -73,8 +73,8 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
 
         protected override Room CreateNewRoom() => new Room
         {
-            Name = { Value = $"{api.LocalUser}'s awesome room" },
-            Type = { Value = MatchType.HeadToHead },
+            Name = $"{api.LocalUser}'s awesome room",
+            Type = MatchType.HeadToHead,
         };
 
         protected override RoomSubScreen CreateRoomSubScreen(Room room) => new MultiplayerMatchSubScreen(room);

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerMatchSongSelect.cs

@@ -24,6 +24,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         [Resolved]
         private OngoingOperationTracker operationTracker { get; set; } = null!;
 
+        private readonly Room room;
         private readonly IBindable<bool> operationInProgress = new Bindable<bool>();
         private readonly PlaylistItem? itemToEdit;
 
@@ -38,6 +39,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         public MultiplayerMatchSongSelect(Room room, PlaylistItem? itemToEdit = null)
             : base(room, itemToEdit)
         {
+            this.room = room;
             this.itemToEdit = itemToEdit;
         }
 
@@ -111,8 +113,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
             }
             else
             {
-                Playlist.Clear();
-                Playlist.Add(item);
+                room.Playlist = [item];
                 this.Exit();
             }
 

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerMatchSubScreen.cs

@@ -1,13 +1,12 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
+using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Logging;
@@ -45,17 +44,17 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         public override string ShortTitle => "room";
 
         [Resolved]
-        private MultiplayerClient client { get; set; }
+        private MultiplayerClient client { get; set; } = null!;
 
         [Resolved(canBeNull: true)]
-        private OsuGame game { get; set; }
+        private OsuGame? game { get; set; }
 
-        private AddItemButton addItemButton;
+        private AddItemButton addItemButton = null!;
 
         public MultiplayerMatchSubScreen(Room room)
             : base(room)
         {
-            Title = room.RoomID.Value == null ? "New room" : room.Name.Value;
+            Title = room.RoomID == null ? "New room" : room.Name;
             Activity.Value = new UserActivity.InLobby(room);
         }
 
@@ -95,7 +94,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
                     },
                     Content = new[]
                     {
-                        new Drawable[]
+                        new Drawable?[]
                         {
                             // Participants column
                             new GridContainer
@@ -139,10 +138,11 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
                                     null,
                                     new Drawable[]
                                     {
-                                        new MultiplayerPlaylist
+                                        new MultiplayerPlaylist(Room)
                                         {
                                             RelativeSizeAxes = Axes.Both,
-                                            RequestEdit = OpenSongSelection
+                                            RequestEdit = OpenSongSelection,
+                                            SelectedItem = SelectedItem
                                         }
                                     },
                                     new[]
@@ -220,7 +220,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         /// Opens the song selection screen to add or edit an item.
         /// </summary>
         /// <param name="itemToEdit">An optional playlist item to edit. If null, a new item will be added instead.</param>
-        internal void OpenSongSelection(PlaylistItem itemToEdit = null)
+        internal void OpenSongSelection(PlaylistItem? itemToEdit = null)
         {
             if (!this.IsCurrentScreen())
                 return;
@@ -228,9 +228,15 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
             this.Push(new MultiplayerMatchSongSelect(Room, itemToEdit));
         }
 
-        protected override Drawable CreateFooter() => new MultiplayerMatchFooter();
+        protected override Drawable CreateFooter() => new MultiplayerMatchFooter
+        {
+            SelectedItem = SelectedItem
+        };
 
-        protected override RoomSettingsOverlay CreateRoomSettingsOverlay(Room room) => new MultiplayerMatchSettingsOverlay(room);
+        protected override RoomSettingsOverlay CreateRoomSettingsOverlay(Room room) => new MultiplayerMatchSettingsOverlay(room)
+        {
+            SelectedItem = SelectedItem
+        };
 
         protected override void UpdateMods()
         {
@@ -245,7 +251,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         }
 
         [Resolved(canBeNull: true)]
-        private IDialogOverlay dialogOverlay { get; set; }
+        private IDialogOverlay? dialogOverlay { get; set; }
 
         private bool exitConfirmed;
 
@@ -275,8 +281,8 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
             return base.OnExiting(e);
         }
 
-        private ModSettingChangeTracker modSettingChangeTracker;
-        private ScheduledDelegate debouncedModSettingsUpdate;
+        private ModSettingChangeTracker? modSettingChangeTracker;
+        private ScheduledDelegate? debouncedModSettingsUpdate;
 
         private void onUserModsChanged(ValueChangedEvent<IReadOnlyList<Mod>> mods)
         {
@@ -352,7 +358,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
             Activity.Value = new UserActivity.InLobby(Room);
         }
 
-        private bool localUserCanAddItem => client.IsHost || Room.QueueMode.Value != QueueMode.HostOnly;
+        private bool localUserCanAddItem => client.IsHost || Room.QueueMode != QueueMode.HostOnly;
 
         private void updateCurrentItem()
         {
@@ -422,7 +428,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
                 return;
 
             // If there's only one playlist item and we are the host, assume we want to change it. Else add a new one.
-            PlaylistItem itemToEdit = client.IsHost && Room.Playlist.Count == 1 ? Room.Playlist.Single() : null;
+            PlaylistItem? itemToEdit = client.IsHost && Room.Playlist.Count == 1 ? Room.Playlist.Single() : null;
 
             OpenSongSelection(itemToEdit);
 
@@ -434,7 +440,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         {
             base.Dispose(isDisposing);
 
-            if (client != null)
+            if (client.IsNotNull())
             {
                 client.RoomUpdated -= onRoomUpdated;
                 client.LoadRequested -= onLoadRequested;

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerPlayer.cs

@@ -1,14 +1,13 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Diagnostics;
 using System.Linq;
 using System.Threading.Tasks;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
+using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Logging;
 using osu.Framework.Screens;
 using osu.Game.Graphics.UserInterface;
@@ -29,17 +28,15 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         protected override UserActivity InitialActivity => new UserActivity.InMultiplayerGame(Beatmap.Value.BeatmapInfo, Ruleset.Value);
 
         [Resolved]
-        private MultiplayerClient client { get; set; }
+        private MultiplayerClient client { get; set; } = null!;
 
-        private IBindable<bool> isConnected;
+        private IBindable<bool> isConnected = null!;
 
         private readonly TaskCompletionSource<bool> resultsReady = new TaskCompletionSource<bool>();
-
         private readonly MultiplayerRoomUser[] users;
 
-        private LoadingLayer loadingDisplay;
-
-        private MultiplayerGameplayLeaderboard multiplayerLeaderboard;
+        private LoadingLayer loadingDisplay = null!;
+        private MultiplayerGameplayLeaderboard multiplayerLeaderboard = null!;
 
         /// <summary>
         /// Construct a multiplayer player.
@@ -53,8 +50,8 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
                 AllowPause = false,
                 AllowRestart = false,
                 AllowFailAnimation = false,
-                AllowSkipping = room.AutoSkip.Value,
-                AutomaticallySkipIntro = room.AutoSkip.Value,
+                AllowSkipping = room.AutoSkip,
+                AutomaticallySkipIntro = room.AutoSkip,
                 AlwaysShowLeaderboard = true,
             })
         {
@@ -153,7 +150,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
             GameplayClockContainer.Reset();
         }
 
-        private void failAndBail(string message = null)
+        private void failAndBail(string? message = null)
         {
             if (!string.IsNullOrEmpty(message))
                 Logger.Log(message, LoggingTarget.Runtime, LogLevel.Important);
@@ -196,14 +193,14 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
 
         protected override ResultsScreen CreateResults(ScoreInfo score)
         {
-            Debug.Assert(Room.RoomID.Value != null);
+            Debug.Assert(Room.RoomID != null);
 
             return multiplayerLeaderboard.TeamScores.Count == 2
-                ? new MultiplayerTeamResultsScreen(score, Room.RoomID.Value.Value, PlaylistItem, multiplayerLeaderboard.TeamScores)
+                ? new MultiplayerTeamResultsScreen(score, Room.RoomID.Value, PlaylistItem, multiplayerLeaderboard.TeamScores)
                 {
                     ShowUserStatistics = true,
                 }
-                : new MultiplayerResultsScreen(score, Room.RoomID.Value.Value, PlaylistItem)
+                : new MultiplayerResultsScreen(score, Room.RoomID.Value, PlaylistItem)
                 {
                     ShowUserStatistics = true
                 };
@@ -213,7 +210,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         {
             base.Dispose(isDisposing);
 
-            if (client != null)
+            if (client.IsNotNull())
             {
                 client.GameplayStarted -= onGameplayStarted;
                 client.ResultsReady -= onResultsReady;

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerRoomManager.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Diagnostics;
 using osu.Framework.Allocation;
@@ -18,12 +16,12 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
     public partial class MultiplayerRoomManager : RoomManager
     {
         [Resolved]
-        private MultiplayerClient multiplayerClient { get; set; }
+        private MultiplayerClient multiplayerClient { get; set; } = null!;
 
-        public override void CreateRoom(Room room, Action<Room> onSuccess = null, Action<string> onError = null)
-            => base.CreateRoom(room, r => joinMultiplayerRoom(r, r.Password.Value, onSuccess, onError), onError);
+        public override void CreateRoom(Room room, Action<Room>? onSuccess = null, Action<string>? onError = null)
+            => base.CreateRoom(room, r => joinMultiplayerRoom(r, r.Password, onSuccess, onError), onError);
 
-        public override void JoinRoom(Room room, string password = null, Action<Room> onSuccess = null, Action<string> onError = null)
+        public override void JoinRoom(Room room, string? password = null, Action<Room>? onSuccess = null, Action<string>? onError = null)
         {
             if (!multiplayerClient.IsConnected.Value)
             {
@@ -33,7 +31,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
 
             // this is done here as a pre-check to avoid clicking on already closed rooms in the lounge from triggering a server join.
             // should probably be done at a higher level, but due to the current structure of things this is the easiest place for now.
-            if (room.Status.Value is RoomStatusEnded)
+            if (room.Status is RoomStatusEnded)
             {
                 onError?.Invoke("Cannot join an ended room.");
                 return;
@@ -51,9 +49,9 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
             multiplayerClient.LeaveRoom();
         }
 
-        private void joinMultiplayerRoom(Room room, string password, Action<Room> onSuccess = null, Action<string> onError = null)
+        private void joinMultiplayerRoom(Room room, string? password, Action<Room>? onSuccess = null, Action<string>? onError = null)
         {
-            Debug.Assert(room.RoomID.Value != null);
+            Debug.Assert(room.RoomID != null);
 
             multiplayerClient.JoinRoom(room, password).ContinueWith(t =>
             {

osu.Game/Screens/OnlinePlay/OnlinePlayComposite.cs

@@ -1,115 +0,0 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-#nullable disable
-
-using System;
-using osu.Framework.Allocation;
-using osu.Framework.Bindables;
-using osu.Framework.Graphics.Containers;
-using osu.Game.Online.API.Requests.Responses;
-using osu.Game.Online.Multiplayer;
-using osu.Game.Online.Rooms;
-using osu.Game.Screens.OnlinePlay.Match;
-
-namespace osu.Game.Screens.OnlinePlay
-{
-    /// <summary>
-    /// A <see cref="CompositeDrawable"/> that exposes bindables for <see cref="Room"/> properties.
-    /// </summary>
-    public partial class OnlinePlayComposite : CompositeDrawable
-    {
-        [Resolved(typeof(Room))]
-        protected Bindable<long?> RoomID { get; private set; }
-
-        [Resolved(typeof(Room), nameof(Room.Name))]
-        protected Bindable<string> RoomName { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<APIUser> Host { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<RoomStatus> Status { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<MatchType> Type { get; private set; }
-
-        /// <summary>
-        /// The currently selected item in the <see cref="RoomSubScreen"/>, or the current item from <see cref="Playlist"/>
-        /// if this <see cref="OnlinePlayComposite"/> is not within a <see cref="RoomSubScreen"/>.
-        /// </summary>
-        [Resolved(typeof(Room))]
-        protected Bindable<PlaylistItem> CurrentPlaylistItem { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<Room.RoomPlaylistItemStats> PlaylistItemStats { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected BindableList<PlaylistItem> Playlist { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<Room.RoomDifficultyRange> DifficultyRange { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<RoomCategory> Category { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected BindableList<APIUser> RecentParticipants { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<int> ParticipantCount { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<int?> MaxParticipants { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<int?> MaxAttempts { get; private set; }
-
-        [Resolved(typeof(Room))]
-        public Bindable<PlaylistAggregateScore> UserScore { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<DateTimeOffset?> StartDate { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<DateTimeOffset?> EndDate { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<RoomAvailability> Availability { get; private set; }
-
-        [Resolved(typeof(Room))]
-        public Bindable<string> Password { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<TimeSpan?> Duration { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<QueueMode> QueueMode { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<TimeSpan> AutoStartDuration { get; private set; }
-
-        [Resolved(typeof(Room))]
-        protected Bindable<bool> AutoSkip { get; private set; }
-
-        [Resolved(CanBeNull = true)]
-        private IBindable<PlaylistItem> subScreenSelectedItem { get; set; }
-
-        protected override void LoadComplete()
-        {
-            base.LoadComplete();
-
-            subScreenSelectedItem?.BindValueChanged(_ => UpdateSelectedItem());
-            Playlist.BindCollectionChanged((_, _) => UpdateSelectedItem(), true);
-        }
-
-        protected void UpdateSelectedItem()
-        {
-            // null room ID means this is a room in the process of being created.
-            if (RoomID.Value == null)
-                CurrentPlaylistItem.Value = Playlist.GetCurrentItem();
-            else if (subScreenSelectedItem != null)
-                CurrentPlaylistItem.Value = subScreenSelectedItem.Value;
-        }
-    }
-}

osu.Game/Screens/OnlinePlay/OnlinePlaySongSelect.cs

@@ -32,9 +32,6 @@ namespace osu.Game.Screens.OnlinePlay
 
         public override bool AllowEditing => false;
 
-        [Resolved(typeof(Room), nameof(Room.Playlist))]
-        protected BindableList<PlaylistItem> Playlist { get; private set; } = null!;
-
         [Resolved]
         private RulesetStore rulesets { get; set; } = null!;
 

osu.Game/Screens/OnlinePlay/Playlists/PlaylistsLoungeSubScreen.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
@@ -22,9 +20,9 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
     public partial class PlaylistsLoungeSubScreen : LoungeSubScreen
     {
         [Resolved]
-        private IAPIProvider api { get; set; }
+        private IAPIProvider api { get; set; } = null!;
 
-        private Dropdown<PlaylistsCategory> categoryDropdown;
+        private Dropdown<PlaylistsCategory> categoryDropdown = null!;
 
         protected override IEnumerable<Drawable> CreateFilterControls()
         {
@@ -67,8 +65,8 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
         {
             return new Room
             {
-                Name = { Value = $"{api.LocalUser}'s awesome playlist" },
-                Type = { Value = MatchType.Playlists }
+                Name = $"{api.LocalUser}'s awesome playlist",
+                Type = MatchType.Playlists
             };
         }
 

osu.Game/Screens/OnlinePlay/Playlists/PlaylistsPlayer.cs

@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Diagnostics;
 using System.Linq;
@@ -21,11 +19,11 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
 {
     public partial class PlaylistsPlayer : RoomSubmittingPlayer
     {
-        public Action Exited;
+        public Action? Exited;
 
         protected override UserActivity InitialActivity => new UserActivity.InPlaylistGame(Beatmap.Value.BeatmapInfo, Ruleset.Value);
 
-        public PlaylistsPlayer(Room room, PlaylistItem playlistItem, PlayerConfiguration configuration = null)
+        public PlaylistsPlayer(Room room, PlaylistItem playlistItem, PlayerConfiguration? configuration = null)
             : base(room, playlistItem, configuration)
         {
         }
@@ -57,8 +55,8 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
 
         protected override ResultsScreen CreateResults(ScoreInfo score)
         {
-            Debug.Assert(Room.RoomID.Value != null);
-            return new PlaylistItemUserResultsScreen(score, Room.RoomID.Value.Value, PlaylistItem)
+            Debug.Assert(Room.RoomID != null);
+            return new PlaylistItemUserResultsScreen(score, Room.RoomID.Value, PlaylistItem)
             {
                 AllowRetry = true,
                 ShowUserStatistics = true,

osu.Game/Screens/OnlinePlay/Playlists/PlaylistsReadyButton.cs

@@ -1,9 +1,8 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
+using System.ComponentModel;
 using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
@@ -17,20 +16,14 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
 {
     public partial class PlaylistsReadyButton : ReadyButton
     {
-        [Resolved(typeof(Room), nameof(Room.EndDate))]
-        private Bindable<DateTimeOffset?> endDate { get; set; }
-
-        [Resolved(typeof(Room), nameof(Room.MaxAttempts))]
-        private Bindable<int?> maxAttempts { get; set; }
-
-        [Resolved(typeof(Room), nameof(Room.UserScore))]
-        private Bindable<PlaylistAggregateScore> userScore { get; set; }
-
         [Resolved]
-        private IBindable<WorkingBeatmap> gameBeatmap { get; set; }
+        private IBindable<WorkingBeatmap> gameBeatmap { get; set; } = null!;
 
-        public PlaylistsReadyButton()
+        private readonly Room room;
+
+        public PlaylistsReadyButton(Room room)
         {
+            this.room = room;
             Text = "Start";
         }
 
@@ -46,15 +39,24 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
         {
             base.LoadComplete();
 
-            userScore.BindValueChanged(aggregate =>
-            {
-                if (maxAttempts.Value == null)
-                    return;
+            room.PropertyChanged += onRoomPropertyChanged;
+            updateRoomUserScore();
+        }
 
-                int remaining = maxAttempts.Value.Value - aggregate.NewValue.PlaylistItemAttempts.Sum(a => a.Attempts);
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(Room.UserScore))
+                updateRoomUserScore();
+        }
 
-                hasRemainingAttempts = remaining > 0;
-            });
+        private void updateRoomUserScore()
+        {
+            if (room.MaxAttempts == null || room.UserScore == null)
+                return;
+
+            int remaining = room.MaxAttempts.Value - room.UserScore.PlaylistItemAttempts.Sum(a => a.Attempts);
+
+            hasRemainingAttempts = remaining > 0;
         }
 
         protected override void Update()
@@ -80,6 +82,12 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
 
         private bool enoughTimeLeft =>
             // This should probably consider the length of the currently selected item, rather than a constant 30 seconds.
-            endDate.Value != null && DateTimeOffset.UtcNow.AddSeconds(30).AddMilliseconds(gameBeatmap.Value.Track.Length) < endDate.Value;
+            room.EndDate != null && DateTimeOffset.UtcNow.AddSeconds(30).AddMilliseconds(gameBeatmap.Value.Track.Length) < room.EndDate;
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            room.PropertyChanged -= onRoomPropertyChanged;
+        }
     }
 }

osu.Game/Screens/OnlinePlay/Playlists/PlaylistsRoomFooter.cs

@@ -1,26 +1,25 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
+using osu.Game.Online.Rooms;
 using osuTK;
 
 namespace osu.Game.Screens.OnlinePlay.Playlists
 {
     public partial class PlaylistsRoomFooter : CompositeDrawable
     {
-        public Action OnStart;
+        public Action? OnStart;
 
-        public PlaylistsRoomFooter()
+        public PlaylistsRoomFooter(Room room)
         {
             RelativeSizeAxes = Axes.Both;
 
             InternalChildren = new[]
             {
-                new PlaylistsReadyButton
+                new PlaylistsReadyButton(room)
                 {
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,

osu.Game/Screens/OnlinePlay/Playlists/PlaylistsRoomSettingsOverlay.cs

@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Specialized;
+using System.ComponentModel;
 using System.Linq;
 using Humanizer;
 using Humanizer.Localisation;
@@ -25,6 +26,7 @@ using osu.Game.Screens.OnlinePlay.Match.Components;
 using osuTK;
 using osu.Game.Localisation;
 using osu.Game.Rulesets;
+using Container = osu.Framework.Graphics.Containers.Container;
 
 namespace osu.Game.Screens.OnlinePlay.Playlists
 {
@@ -45,14 +47,14 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
 
         protected override void SelectBeatmap() => settings.SelectBeatmap();
 
-        protected override OnlinePlayComposite CreateSettings(Room room) => settings = new MatchSettings(room)
+        protected override Drawable CreateSettings(Room room) => settings = new MatchSettings(room)
         {
             RelativeSizeAxes = Axes.Both,
             RelativePositionAxes = Axes.Y,
             EditPlaylist = () => EditPlaylist?.Invoke()
         };
 
-        protected partial class MatchSettings : OnlinePlayComposite
+        protected partial class MatchSettings : CompositeDrawable
         {
             private const float disabled_alpha = 0.2f;
 
@@ -142,7 +144,8 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
                                                             {
                                                                 RelativeSizeAxes = Axes.X,
                                                                 TabbableContentContainer = this,
-                                                                LengthLimit = 100
+                                                                LengthLimit = 100,
+                                                                Text = room.Name
                                                             },
                                                         },
                                                         new Section("Duration")
@@ -313,12 +316,6 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
                     loadingLayer = new LoadingLayer(true)
                 };
 
-                RoomName.BindValueChanged(name => NameField.Text = name.NewValue, true);
-                Availability.BindValueChanged(availability => AvailabilityPicker.Current.Value = availability.NewValue, true);
-                MaxParticipants.BindValueChanged(count => MaxParticipantsField.Text = count.NewValue?.ToString(), true);
-                MaxAttempts.BindValueChanged(count => MaxAttemptsField.Text = count.NewValue?.ToString(), true);
-                Duration.BindValueChanged(duration => DurationField.Current.Value = duration.NewValue ?? TimeSpan.FromMinutes(30), true);
-
                 DurationField.Current.BindValueChanged(duration =>
                 {
                     if (hasValidDuration)
@@ -332,11 +329,72 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
 
                 localUser = api.LocalUser.GetBoundCopy();
                 localUser.BindValueChanged(populateDurations, true);
-
-                playlist.Items.BindTo(Playlist);
-                Playlist.BindCollectionChanged(onPlaylistChanged, true);
             }
 
+            protected override void LoadComplete()
+            {
+                base.LoadComplete();
+
+                room.PropertyChanged += onRoomPropertyChanged;
+
+                updateRoomName();
+                updateRoomAvailability();
+                updateRoomMaxParticipants();
+                updateRoomDuration();
+                updateRoomMaxAttempts();
+                updateRoomPlaylist();
+
+                playlist.Items.BindCollectionChanged((_, __) => room.Playlist = playlist.Items.ToArray());
+            }
+
+            private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+            {
+                switch (e.PropertyName)
+                {
+                    case nameof(Room.Name):
+                        updateRoomName();
+                        break;
+
+                    case nameof(Room.Availability):
+                        updateRoomAvailability();
+                        break;
+
+                    case nameof(Room.MaxParticipants):
+                        updateRoomMaxParticipants();
+                        break;
+
+                    case nameof(Room.Duration):
+                        updateRoomDuration();
+                        break;
+
+                    case nameof(Room.MaxAttempts):
+                        updateRoomMaxAttempts();
+                        break;
+
+                    case nameof(Room.Playlist):
+                        updateRoomPlaylist();
+                        break;
+                }
+            }
+
+            private void updateRoomName()
+                => NameField.Text = room.Name;
+
+            private void updateRoomAvailability()
+                => AvailabilityPicker.Current.Value = room.Availability;
+
+            private void updateRoomMaxParticipants()
+                => MaxParticipantsField.Text = room.MaxParticipants?.ToString();
+
+            private void updateRoomDuration()
+                => DurationField.Current.Value = room.Duration ?? TimeSpan.FromMinutes(30);
+
+            private void updateRoomMaxAttempts()
+                => MaxAttemptsField.Text = room.MaxAttempts?.ToString();
+
+            private void updateRoomPlaylist()
+                => playlist.Items.ReplaceRange(0, playlist.Items.Count, room.Playlist);
+
             private void populateDurations(ValueChangedEvent<APIUser> user)
             {
                 // roughly correct (see https://github.com/Humanizr/Humanizer/blob/18167e56c082449cc4fe805b8429e3127a7b7f93/readme.md?plain=1#L427)
@@ -370,9 +428,9 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
             public void SelectBeatmap() => editPlaylistButton.TriggerClick();
 
             private void onPlaylistChanged(object? sender, NotifyCollectionChangedEventArgs e) =>
-                playlistLength.Text = $"Length: {Playlist.GetTotalDuration(rulesets)}";
+                playlistLength.Text = $"Length: {room.Playlist.GetTotalDuration(rulesets)}";
 
-            private bool hasValidSettings => RoomID.Value == null && NameField.Text.Length > 0 && Playlist.Count > 0
+            private bool hasValidSettings => room.RoomID == null && NameField.Text.Length > 0 && room.Playlist.Count > 0
                                              && hasValidDuration;
 
             private bool hasValidDuration => DurationField.Current.Value <= TimeSpan.FromDays(14) || localUser.Value.IsSupporter;
@@ -384,20 +442,11 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
 
                 hideError();
 
-                RoomName.Value = NameField.Text;
-                Availability.Value = AvailabilityPicker.Current.Value;
-
-                if (int.TryParse(MaxParticipantsField.Text, out int max))
-                    MaxParticipants.Value = max;
-                else
-                    MaxParticipants.Value = null;
-
-                if (int.TryParse(MaxAttemptsField.Text, out max))
-                    MaxAttempts.Value = max;
-                else
-                    MaxAttempts.Value = null;
-
-                Duration.Value = DurationField.Current.Value;
+                room.Name = NameField.Text;
+                room.Availability = AvailabilityPicker.Current.Value;
+                room.MaxParticipants = int.TryParse(MaxParticipantsField.Text, out int maxParticipants) ? maxParticipants : null;
+                room.MaxAttempts = int.TryParse(MaxAttemptsField.Text, out int maxAttempts) ? maxAttempts : null;
+                room.Duration = DurationField.Current.Value;
 
                 loadingLayer.Show();
                 manager?.CreateRoom(room, onSuccess, onError);
@@ -422,7 +471,7 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
                                               .Select(int.Parse)
                                               .ToArray();
 
-                    foreach (var item in Playlist)
+                    foreach (var item in room.Playlist)
                     {
                         if (invalidBeatmapIDs.Contains(item.Beatmap.OnlineID))
                             item.MarkInvalid();
@@ -436,6 +485,12 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
                 ErrorText.FadeIn(50);
                 loadingLayer.Hide();
             }
+
+            protected override void Dispose(bool isDisposing)
+            {
+                base.Dispose(isDisposing);
+                room.PropertyChanged -= onRoomPropertyChanged;
+            }
         }
 
         public partial class CreateRoomButton : RoundedButton

osu.Game/Screens/OnlinePlay/Playlists/PlaylistsRoomSubScreen.cs

@@ -1,11 +1,9 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
+using System.ComponentModel;
 using System.Diagnostics;
 using System.Linq;
-using JetBrains.Annotations;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
@@ -22,6 +20,7 @@ using osu.Game.Screens.Play;
 using osu.Game.Screens.Play.HUD;
 using osu.Game.Users;
 using osuTK;
+using Container = osu.Framework.Graphics.Containers.Container;
 
 namespace osu.Game.Screens.OnlinePlay.Playlists
 {
@@ -33,20 +32,23 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
 
         private readonly IBindable<bool> isIdle = new BindableBool();
 
-        private MatchLeaderboard leaderboard;
-        private SelectionPollingComponent selectionPollingComponent;
+        [Resolved(CanBeNull = true)]
+        private IdleTracker? idleTracker { get; set; }
 
-        private FillFlowContainer progressSection;
+        private MatchLeaderboard leaderboard = null!;
+        private SelectionPollingComponent selectionPollingComponent = null!;
+        private FillFlowContainer progressSection = null!;
+        private DrawableRoomPlaylist drawablePlaylist = null!;
 
         public PlaylistsRoomSubScreen(Room room)
             : base(room, false) // Editing is temporarily not allowed.
         {
-            Title = room.RoomID.Value == null ? "New playlist" : room.Name.Value;
+            Title = room.RoomID == null ? "New playlist" : room.Name;
             Activity.Value = new UserActivity.InLobby(room);
         }
 
-        [BackgroundDependencyLoader(true)]
-        private void load([CanBeNull] IdleTracker idleTracker)
+        [BackgroundDependencyLoader]
+        private void load()
         {
             if (idleTracker != null)
                 isIdle.BindTo(idleTracker.IsIdle);
@@ -59,19 +61,47 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
             base.LoadComplete();
 
             isIdle.BindValueChanged(_ => updatePollingRate(), true);
-            RoomId.BindValueChanged(id =>
-            {
-                if (id.NewValue != null)
-                {
-                    // Set the first playlist item.
-                    // This is scheduled since updating the room and playlist may happen in an arbitrary order (via Room.CopyFrom()).
-                    Schedule(() => SelectedItem.Value = Room.Playlist.FirstOrDefault());
-                }
-            }, true);
 
-            Room.MaxAttempts.BindValueChanged(_ => progressSection.Alpha = Room.MaxAttempts.Value != null ? 1 : 0, true);
+            Room.PropertyChanged += onRoomPropertyChanged;
+            updateSetupState();
+            updateRoomMaxAttempts();
+            updateRoomPlaylist();
         }
 
+        private void onRoomPropertyChanged(object? sender, PropertyChangedEventArgs e)
+        {
+            switch (e.PropertyName)
+            {
+                case nameof(Room.RoomID):
+                    updateSetupState();
+                    break;
+
+                case nameof(Room.MaxAttempts):
+                    updateRoomMaxAttempts();
+                    break;
+
+                case nameof(Room.Playlist):
+                    updateRoomPlaylist();
+                    break;
+            }
+        }
+
+        private void updateSetupState()
+        {
+            if (Room.RoomID != null)
+            {
+                // Set the first playlist item.
+                // This is scheduled since updating the room and playlist may happen in an arbitrary order (via Room.CopyFrom()).
+                Schedule(() => SelectedItem.Value = Room.Playlist.FirstOrDefault());
+            }
+        }
+
+        private void updateRoomMaxAttempts()
+            => progressSection.Alpha = Room.MaxAttempts != null ? 1 : 0;
+
+        private void updateRoomPlaylist()
+            => drawablePlaylist.Items.ReplaceRange(0, drawablePlaylist.Items.Count, Room.Playlist);
+
         protected override Drawable CreateMainContent() => new Container
         {
             RelativeSizeAxes = Axes.Both,
@@ -92,7 +122,7 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
                     },
                     Content = new[]
                     {
-                        new Drawable[]
+                        new Drawable?[]
                         {
                             // Playlist items column
                             new GridContainer
@@ -101,20 +131,19 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
                                 Padding = new MarginPadding { Right = 5 },
                                 Content = new[]
                                 {
-                                    new Drawable[] { new OverlinedPlaylistHeader(), },
+                                    new Drawable[] { new OverlinedPlaylistHeader(Room), },
                                     new Drawable[]
                                     {
-                                        new DrawableRoomPlaylist
+                                        drawablePlaylist = new DrawableRoomPlaylist
                                         {
                                             RelativeSizeAxes = Axes.Both,
-                                            Items = { BindTarget = Room.Playlist },
                                             SelectedItem = { BindTarget = SelectedItem },
                                             AllowSelection = true,
                                             AllowShowingResults = true,
                                             RequestResults = item =>
                                             {
-                                                Debug.Assert(RoomId.Value != null);
-                                                ParentScreen?.Push(new PlaylistItemUserResultsScreen(null, RoomId.Value.Value, item));
+                                                Debug.Assert(Room.RoomID != null);
+                                                ParentScreen?.Push(new PlaylistItemUserResultsScreen(null, Room.RoomID.Value, item));
                                             }
                                         }
                                     },
@@ -183,7 +212,7 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
                                             Children = new Drawable[]
                                             {
                                                 new OverlinedHeader("Progress"),
-                                                new RoomLocalUserInfo(),
+                                                new RoomLocalUserInfo(Room),
                                             }
                                         },
                                     },
@@ -191,7 +220,7 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
                                     {
                                         new OverlinedHeader("Leaderboard")
                                     },
-                                    new Drawable[] { leaderboard = new MatchLeaderboard { RelativeSizeAxes = Axes.Both }, },
+                                    new Drawable[] { leaderboard = new MatchLeaderboard(Room) { RelativeSizeAxes = Axes.Both }, },
                                 },
                                 RowDimensions = new[]
                                 {
@@ -224,7 +253,7 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
             }
         };
 
-        protected override Drawable CreateFooter() => new PlaylistsRoomFooter
+        protected override Drawable CreateFooter() => new PlaylistsRoomFooter(Room)
         {
             OnStart = StartPlay
         };
@@ -248,5 +277,11 @@ namespace osu.Game.Screens.OnlinePlay.Playlists
         {
             Exited = () => leaderboard.RefetchScores()
         });
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            Room.PropertyChanged -= onRoomPropertyChanged;
+        }
     }
 }