Use more generic way to apply the value to the stage runner.

osu.Game.Rulesets.Karaoke/Stages/Drawables/DrawableStage.cs

@@ -5,13 +5,11 @@
 using System.Collections.Generic;
 using System.Linq;
 using osu.Framework.Allocation;
-using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Game.Beatmaps;
 using osu.Game.Rulesets.Karaoke.Beatmaps;
 using osu.Game.Rulesets.Karaoke.Mods;
-using osu.Game.Rulesets.Karaoke.Objects;
 using osu.Game.Rulesets.Karaoke.Stages.Infos;
 using osu.Game.Rulesets.Karaoke.Stages.Infos.Preview;
 using osu.Game.Rulesets.Karaoke.Stages.Infos.Types;
@@ -31,6 +29,7 @@ public partial class DrawableStage : Container
     [Cached(typeof(IStagePlayfieldRunner))]
     private readonly StagePlayfieldRunner stagePlayfieldRunner = new();
 
+    [Cached(typeof(IStageElementRunner))]
     private readonly StageElementRunner stageElementRunner = new();
 
     [BackgroundDependencyLoader]
@@ -59,18 +58,10 @@ public void TriggerRecalculate(KaraokeBeatmap karaokeBeatmap, IReadOnlyList<Mod>
             calculatedProperty.ValidateCalculatedProperty(karaokeBeatmap);
 
         bool scorable = karaokeBeatmap.IsScorable();
-        var playfieldCommandProvider = stageInfo.CreatePlayfieldCommandProvider(scorable);
-        stagePlayfieldRunner.UpdateCommandGenerator(playfieldCommandProvider);
 
-        var stageElementProvider = stageInfo.CreateStageElementProvider(scorable);
-
-        if (stageElementProvider != null)
-            stageElementRunner.UpdateCommandGenerator(stageElementProvider);
-
-        // todo: should handle the note case.
-        var lyricCommandProvider = stageInfo.CreateHitObjectCommandProvider<Lyric>();
-        if (lyricCommandProvider != null)
-            stageRunner.UpdateCommandGenerator(lyricCommandProvider);
+        stageRunner.OnStageInfoChanged(stageInfo, scorable, mods);
+        stagePlayfieldRunner.OnStageInfoChanged(stageInfo, scorable, mods);
+        stageElementRunner.OnStageInfoChanged(stageInfo, scorable, mods);
     }
 
     public override void Add(Drawable drawable)

osu.Game.Rulesets.Karaoke/Stages/Drawables/StageElementRunner.cs

@@ -1,18 +1,26 @@
 // Copyright (c) andy840119 <[email protected]>. Licensed under the GPL Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System.Collections.Generic;
 using osu.Framework.Graphics.Containers;
+using osu.Game.Rulesets.Karaoke.Stages.Infos;
+using osu.Game.Rulesets.Mods;
 
 namespace osu.Game.Rulesets.Karaoke.Stages.Drawables;
 
-public class StageElementRunner : IStageElementRunner
+public class StageElementRunner : StageRunner, IStageElementRunner
 {
     private IStageElementProvider? elementProvider;
     private Container? elementContainer;
 
-    public void UpdateCommandGenerator(IStageElementProvider provider)
+    public override void OnStageInfoChanged(StageInfo stageInfo, bool scorable, IReadOnlyList<Mod> mods)
+    {
+        elementProvider = stageInfo.CreateStageElementProvider(scorable);
+        applyTransforms();
+    }
+
+    public override void TriggerUpdateCommand()
     {
-        elementProvider = provider;
         applyTransforms();
     }
 

osu.Game.Rulesets.Karaoke/Stages/Drawables/StageHitObjectRunner.cs

@@ -4,26 +4,28 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using osu.Framework.Graphics;
+using osu.Game.Rulesets.Karaoke.Objects;
 using osu.Game.Rulesets.Karaoke.Stages.Commands;
+using osu.Game.Rulesets.Karaoke.Stages.Infos;
+using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Objects.Drawables;
 
 namespace osu.Game.Rulesets.Karaoke.Stages.Drawables;
 
-public partial class StageHitObjectRunner : Component, IStageHitObjectRunner
+public class StageHitObjectRunner : StageRunner, IStageHitObjectRunner
 {
     public event Action? OnCommandUpdated;
 
     private IHitObjectCommandProvider commandProvider = null!;
 
-    public void UpdateCommandGenerator(IHitObjectCommandProvider provider)
+    public override void OnStageInfoChanged(StageInfo stageInfo, bool scorable, IReadOnlyList<Mod> mods)
     {
-        commandProvider = provider;
+        commandProvider = stageInfo.CreateHitObjectCommandProvider<Lyric>()!;
         OnCommandUpdated?.Invoke();
     }
 
-    public void TriggerUpdateCommand()
+    public override void TriggerUpdateCommand()
     {
         OnCommandUpdated?.Invoke();
     }

osu.Game.Rulesets.Karaoke/Stages/Drawables/StagePlayfieldRunner.cs

@@ -4,19 +4,26 @@
 using System.Collections.Generic;
 using System.Linq;
 using osu.Game.Rulesets.Karaoke.Stages.Commands;
+using osu.Game.Rulesets.Karaoke.Stages.Infos;
 using osu.Game.Rulesets.Karaoke.UI;
+using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.UI;
 
 namespace osu.Game.Rulesets.Karaoke.Stages.Drawables;
 
-public class StagePlayfieldRunner : IStagePlayfieldRunner
+public class StagePlayfieldRunner : StageRunner, IStagePlayfieldRunner
 {
     private IPlayfieldCommandProvider? commandProvider;
     private KaraokePlayfield? karaokePlayfield;
 
-    public void UpdateCommandGenerator(IPlayfieldCommandProvider provider)
+    public override void OnStageInfoChanged(StageInfo stageInfo, bool scorable, IReadOnlyList<Mod> mods)
+    {
+        commandProvider = stageInfo.CreatePlayfieldCommandProvider(scorable);
+        applyTransforms();
+    }
+
+    public override void TriggerUpdateCommand()
     {
-        commandProvider = provider;
         applyTransforms();
     }
 

osu.Game.Rulesets.Karaoke/Stages/Drawables/StageRunner.cs

@@ -0,0 +1,15 @@
+// Copyright (c) andy840119 <[email protected]>. Licensed under the GPL Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Collections.Generic;
+using osu.Game.Rulesets.Karaoke.Stages.Infos;
+using osu.Game.Rulesets.Mods;
+
+namespace osu.Game.Rulesets.Karaoke.Stages.Drawables;
+
+public abstract partial class StageRunner
+{
+    public abstract void OnStageInfoChanged(StageInfo stageInfo, bool scorable, IReadOnlyList<Mod> mods);
+
+    public abstract void TriggerUpdateCommand();
+}