Raise platform events on Dispatcher, so exceptions in their handlers can be handled by Dispatcher (#14434)

* Raise BackRequested with Send priority

* Raise InsestsManager events with Send priority

* Raise InputPane events with Send priority

* Raise PlatformSettings events with Send priority

* Redirect some more events to the Dispatcher from TopLevel

src/Android/Avalonia.Android/Platform/AndroidInsetsManager.cs

@@ -8,6 +8,7 @@ using Avalonia.Android.Platform.SkiaPlatform;
 using Avalonia.Animation.Easings;
 using Avalonia.Controls.Platform;
 using Avalonia.Media;
+using Avalonia.Threading;
 using AndroidWindow = Android.Views.Window;
 
 namespace Avalonia.Android.Platform
@@ -40,7 +41,7 @@ namespace Avalonia.Android.Platform
                 if (oldState != value && Build.VERSION.SdkInt <= BuildVersionCodes.Q)
                 {
                     var currentRect = OccludedRect;
-                    StateChanged?.Invoke(this, new InputPaneStateEventArgs(value, _previousRect, currentRect, TimeSpan.Zero, null));
+                    NotifyStateChanged(value, _previousRect, currentRect, TimeSpan.Zero, null);
                     _previousRect = currentRect;
                 }
             }
@@ -151,7 +152,12 @@ namespace Avalonia.Android.Platform
 
         private void NotifySafeAreaChanged(Thickness safeAreaPadding)
         {
-            SafeAreaChanged?.Invoke(this, new SafeAreaChangedArgs(safeAreaPadding));
+            Dispatcher.UIThread.Send(_ => SafeAreaChanged?.Invoke(this, new SafeAreaChangedArgs(safeAreaPadding)));
+        }
+        
+        private void NotifyStateChanged(InputPaneState newState, Rect? startRect, Rect endRect, TimeSpan animationDuration, IEasing easing)
+        {
+            Dispatcher.UIThread.Send(_ => StateChanged?.Invoke(this, new InputPaneStateEventArgs(newState, startRect, endRect, animationDuration, easing)));
         }
 
         public void OnGlobalLayout()
@@ -294,7 +300,7 @@ namespace Avalonia.Android.Platform
                     var duration = TimeSpan.FromMilliseconds(animation.DurationMillis);
 
                     bool isOpening = State == InputPaneState.Open;
-                    StateChanged?.Invoke(this, new InputPaneStateEventArgs(State, isOpening ? upperRect : lowerRect, isOpening ? lowerRect : upperRect, duration, new AnimationEasing(animation.Interpolator)));
+                    NotifyStateChanged(State, isOpening ? upperRect : lowerRect, isOpening ? lowerRect : upperRect, duration, new AnimationEasing(animation.Interpolator));
                 }
             }
 

src/Avalonia.Base/Platform/DefaultPlatformSettings.cs

@@ -3,6 +3,7 @@ using Avalonia.Input;
 using Avalonia.Input.Platform;
 using Avalonia.Media;
 using Avalonia.Metadata;
+using Avalonia.Threading;
 using Avalonia.VisualTree;
 
 namespace Avalonia.Platform
@@ -50,7 +51,8 @@ namespace Avalonia.Platform
 
         protected void OnColorValuesChanged(PlatformColorValues colorValues)
         {
-            ColorValuesChanged?.Invoke(this, colorValues);
+            Dispatcher.UIThread.Send(
+                _ => ColorValuesChanged?.Invoke(this, colorValues));
         }
     }
 }

src/Avalonia.Base/Threading/Dispatcher.Invoke.cs

@@ -635,7 +635,7 @@ public partial class Dispatcher
     /// <remarks>
     /// When on the same thread with Send priority, callback is executed immediately, without changing synchronization context.
     /// </remarks>
-    internal void Send(SendOrPostCallback action, object? arg, DispatcherPriority? priority = null)
+    internal void Send(SendOrPostCallback action, object? arg = null, DispatcherPriority? priority = null)
     {
         _ = action ?? throw new ArgumentNullException(nameof(action));
         priority ??= DispatcherPriority.Send;

src/Avalonia.Controls/Platform/IInputPane.cs

@@ -1,6 +1,7 @@
 using System;
 using Avalonia.Animation.Easings;
 using Avalonia.Metadata;
+using Avalonia.Threading;
 
 namespace Avalonia.Controls.Platform
 {
@@ -26,6 +27,20 @@ namespace Avalonia.Controls.Platform
         event EventHandler<InputPaneStateEventArgs>? StateChanged;
     }
 
+    [PrivateApi]
+    public abstract class InputPaneBase : IInputPane
+    {
+        public virtual InputPaneState State { get; protected set; }
+        public virtual Rect OccludedRect { get; protected set; }
+        public event EventHandler<InputPaneStateEventArgs>? StateChanged;
+
+        protected void OnStateChanged(InputPaneStateEventArgs eventArgs)
+        {
+            Dispatcher.UIThread.Send(
+                _ => StateChanged?.Invoke(this, eventArgs));
+        }
+    }
+    
     /// <summary>
     /// The input pane opened state.
     /// </summary>

src/Avalonia.Controls/Platform/IInsetsManager.cs

@@ -1,11 +1,11 @@
 using System;
 using Avalonia.Media;
 using Avalonia.Metadata;
+using Avalonia.Threading;
 
 #nullable enable
 namespace Avalonia.Controls.Platform
 {
-    [Unstable]
     [NotClientImplementable]
     public interface IInsetsManager
     {
@@ -34,6 +34,23 @@ namespace Avalonia.Controls.Platform
         /// </summary>
         event EventHandler<SafeAreaChangedArgs>? SafeAreaChanged;
     }
+
+    [PrivateApi]
+    public abstract class InsetsManagerBase : IInsetsManager
+    {
+        public virtual bool? IsSystemBarVisible { get; set; }
+        public virtual bool DisplayEdgeToEdge { get; set; }
+        public virtual Thickness SafeAreaPadding { get; protected set; }
+        public virtual Color? SystemBarColor { get; set; }
+        public event EventHandler<SafeAreaChangedArgs>? SafeAreaChanged;
+
+        protected void OnSafeAreaChanged(SafeAreaChangedArgs eventArgs)
+        {
+            Dispatcher.UIThread.Send(
+                _ => SafeAreaChanged?.Invoke(this, eventArgs),
+                null, DispatcherPriority.Send);
+        }
+    }
     
     public class SafeAreaChangedArgs : EventArgs
     {

src/Avalonia.Controls/TopLevel.cs

@@ -272,7 +272,7 @@ namespace Avalonia.Controls
                 systemNavigationManager.BackRequested += (_, e) =>
                 {
                     e.RoutedEvent = BackRequestedEvent;
-                    RaiseEvent(e);
+                    Dispatcher.UIThread.Send(_ => RaiseEvent(e));
                 };
             }
 
@@ -306,7 +306,7 @@ namespace Avalonia.Controls
                 if (backRequested)
                 {
                     var backRequestedEventArgs = new RoutedEventArgs(BackRequestedEvent);
-                    RaiseEvent(backRequestedEventArgs);
+                    Dispatcher.UIThread.Send(_ => RaiseEvent(backRequestedEventArgs));
 
                     e.Handled = backRequestedEventArgs.Handled;
                 }
@@ -739,7 +739,7 @@ namespace Avalonia.Controls
         private void HandleScalingChanged(double scaling)
         {
             LayoutHelper.InvalidateSelfAndChildrenMeasure(this);
-            ScalingChanged?.Invoke(this, EventArgs.Empty);
+            Dispatcher.UIThread.Send(_ => ScalingChanged?.Invoke(this, EventArgs.Empty));
         }
 
         private void HandleTransparencyLevelChanged(WindowTransparencyLevel transparencyLevel)
@@ -786,14 +786,17 @@ namespace Avalonia.Controls
         protected virtual void OnOpened(EventArgs e)
         {
             FrameSize = PlatformImpl?.FrameSize;
-            Opened?.Invoke(this, e);  
+            Dispatcher.UIThread.Send(_ => Opened?.Invoke(this, e));
-        } 
+        }
 
         /// <summary>
         /// Raises the <see cref="Closed"/> event.
         /// </summary>
         /// <param name="e">The event args.</param>
-        protected virtual void OnClosed(EventArgs e) => Closed?.Invoke(this, e);
+        protected virtual void OnClosed(EventArgs e)
+        {
+            Dispatcher.UIThread.Send(_ => Closed?.Invoke(this, e));
+        }
 
         /// <summary>
         /// Tries to get a service from an <see cref="IAvaloniaDependencyResolver"/>, logging a

src/Browser/Avalonia.Browser/BrowserInputPane.cs

@@ -5,17 +5,13 @@ using Avalonia.Controls.Platform;
 
 namespace Avalonia.Browser;
 
-internal class BrowserInputPane : IInputPane
+internal class BrowserInputPane : InputPaneBase
 {
     public BrowserInputPane(JSObject container)
     {
         InputHelper.SubscribeKeyboardGeometryChange(container, OnGeometryChange);
     }
 
-    public InputPaneState State { get; private set; }
-    public Rect OccludedRect { get; private set; }
-    public event EventHandler<InputPaneStateEventArgs>? StateChanged;
-    
     private bool OnGeometryChange(JSObject args)
     {
         var oldState = (OccludedRect, State);
@@ -29,7 +25,7 @@ internal class BrowserInputPane : IInputPane
 
         if (oldState != (OccludedRect, State))
         {
-            StateChanged?.Invoke(this, new InputPaneStateEventArgs(State, null, OccludedRect));
+            OnStateChanged(new InputPaneStateEventArgs(State, null, OccludedRect));
         }
 
         return true;

src/Browser/Avalonia.Browser/BrowserInsetsManager.cs

@@ -10,9 +10,9 @@ using static Avalonia.Controls.Platform.IInsetsManager;
 
 namespace Avalonia.Browser
 {
-    internal class BrowserInsetsManager : IInsetsManager
+    internal class BrowserInsetsManager : InsetsManagerBase
     {
-        public bool? IsSystemBarVisible
+        public override bool? IsSystemBarVisible
         {
             get
             {
@@ -24,11 +24,9 @@ namespace Avalonia.Browser
             }
         }
 
-        public bool DisplayEdgeToEdge { get; set; }
+        public override bool DisplayEdgeToEdge { get; set; }
 
-        public event EventHandler<SafeAreaChangedArgs>? SafeAreaChanged;
+        public override Thickness SafeAreaPadding
-
-        public Thickness SafeAreaPadding
         {
             get
             {
@@ -38,11 +36,11 @@ namespace Avalonia.Browser
             }
         }
 
-        public Color? SystemBarColor { get; set; }
+        public override Color? SystemBarColor { get; set; }
 
         public void NotifySafeAreaPaddingChanged()
         {
-            SafeAreaChanged?.Invoke(this, new SafeAreaChangedArgs(SafeAreaPadding));
+            OnSafeAreaChanged(new SafeAreaChangedArgs(SafeAreaPadding));
         }
     }
 }

src/Windows/Avalonia.Win32/Input/WindowsInputPane.cs

@@ -8,7 +8,7 @@ using MicroCom.Runtime;
 
 namespace Avalonia.Win32.Input;
 
-internal unsafe class WindowsInputPane : IInputPane, IDisposable
+internal unsafe class WindowsInputPane : InputPaneBase, IDisposable
 {
     private static readonly Lazy<bool> s_inputPaneSupported = new(() =>
         WinRTApiInformation.IsTypePresent("Windows.UI.ViewManagement.InputPane")); 
@@ -48,12 +48,6 @@ internal unsafe class WindowsInputPane : IInputPane, IDisposable
 
         return null;
     }
-    
-    public InputPaneState State { get; private set; }
-
-    public Rect OccludedRect { get; private set; }
-
-    public event EventHandler<InputPaneStateEventArgs>? StateChanged;
 
     private void OnStateChanged(bool showing, UnmanagedMethods.RECT? prcInputPaneScreenLocation)
     {
@@ -65,7 +59,7 @@ internal unsafe class WindowsInputPane : IInputPane, IDisposable
 
         if (oldState != (OccludedRect, State))
         {
-            StateChanged?.Invoke(this, new InputPaneStateEventArgs(State, null, OccludedRect));
+            OnStateChanged(new InputPaneStateEventArgs(State, null, OccludedRect));
         }
     }
 

src/iOS/Avalonia.iOS/InsetsManager.cs

@@ -4,7 +4,7 @@ using Avalonia.Media;
 
 namespace Avalonia.iOS;
 
-internal class InsetsManager : IInsetsManager
+internal class InsetsManager : InsetsManagerBase
 {
     private IAvaloniaViewController? _controller;
     private bool _displayEdgeToEdge = true;
@@ -16,13 +16,13 @@ internal class InsetsManager : IInsetsManager
         {
             _controller.SafeAreaPaddingChanged += (_, _) =>
             {
-                SafeAreaChanged?.Invoke(this, new SafeAreaChangedArgs(SafeAreaPadding));
+                OnSafeAreaChanged(new SafeAreaChangedArgs(SafeAreaPadding));
                 DisplayEdgeToEdgeChanged?.Invoke(this, _displayEdgeToEdge);
             };
         }
     }
 
-    public bool? IsSystemBarVisible
+    public override bool? IsSystemBarVisible
     {
         get => _controller?.PrefersStatusBarHidden == false;
         set
@@ -33,10 +33,9 @@ internal class InsetsManager : IInsetsManager
             }
         }
     }
-    public event EventHandler<SafeAreaChangedArgs>? SafeAreaChanged;
     public event EventHandler<bool>? DisplayEdgeToEdgeChanged;
 
-    public bool DisplayEdgeToEdge
+    public override bool DisplayEdgeToEdge
     {
         get => _displayEdgeToEdge;
         set
@@ -45,12 +44,12 @@ internal class InsetsManager : IInsetsManager
             {
                 _displayEdgeToEdge = value;
                 DisplayEdgeToEdgeChanged?.Invoke(this, value);
-                SafeAreaChanged?.Invoke(this, new SafeAreaChangedArgs(SafeAreaPadding));
+                OnSafeAreaChanged(new SafeAreaChangedArgs(SafeAreaPadding));
             }
         }
     }
 
-    public Thickness SafeAreaPadding => _displayEdgeToEdge ? _controller?.SafeAreaPadding ?? default : default;
+    public override Thickness SafeAreaPadding => _displayEdgeToEdge ? _controller?.SafeAreaPadding ?? default : default;
 
-    public Color? SystemBarColor { get; set; }
+    public override Color? SystemBarColor { get; set; }
 }

src/iOS/Avalonia.iOS/UIKitInputPane.cs

@@ -11,7 +11,7 @@ namespace Avalonia.iOS;
 [UnsupportedOSPlatform("tvos")]
 [SupportedOSPlatform("maccatalyst")]
 [SupportedOSPlatform("ios")]
-internal sealed class UIKitInputPane : IInputPane
+internal sealed class UIKitInputPane : InputPaneBase
 {
     public static UIKitInputPane Instance { get; } = new();
     
@@ -24,11 +24,7 @@ internal sealed class UIKitInputPane : IInputPane
             .DefaultCenter
             .AddObserver(UIKeyboard.WillHideNotification, KeyboardDownNotification);
     }
-
+    
-    public InputPaneState State { get; private set; }
-    public Rect OccludedRect { get; private set; }
-    public event EventHandler<InputPaneStateEventArgs>? StateChanged;
-
     private void KeyboardDownNotification(NSNotification obj) => RaiseEventFromNotification(false, obj);
 
     private void KeyboardUpNotification(NSNotification obj) => RaiseEventFromNotification(true, obj);
@@ -38,7 +34,7 @@ internal sealed class UIKitInputPane : IInputPane
         State = isUp ? InputPaneState.Open : InputPaneState.Closed;
 #if MACCATALYST
         OccludedRect = default;
-        StateChanged?.Invoke(this, new InputPaneStateEventArgs(
+        OnStateChanged(new InputPaneStateEventArgs(
             State, null, OccludedRect));
 #else
         var startFrame = UIKeyboard.FrameBeginFromNotification(notification);
@@ -55,7 +51,7 @@ internal sealed class UIKitInputPane : IInputPane
         var startRect = new Rect(startFrame.X, startFrame.Y, startFrame.Width, startFrame.Height);
         OccludedRect = new Rect(endFrame.X, endFrame.Y, endFrame.Width, endFrame.Height);
 
-        StateChanged?.Invoke(this, new InputPaneStateEventArgs(
+        OnStateChanged(new InputPaneStateEventArgs(
             State, startRect, OccludedRect, TimeSpan.FromSeconds(duration), easing));
 #endif
     }