Add ExecuteCommandOnLostFocusBehavior

src/Avalonia.Xaml.Interactions.Custom/ExecuteCommandOnLostFocusBehavior.cs

@@ -0,0 +1,42 @@
+using System.Reactive.Disposables;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+
+namespace Avalonia.Xaml.Interactions.Custom;
+
+/// <summary>
+/// 
+/// </summary>
+public class ExecuteCommandOnLostFocusBehavior : ExecuteCommandBehaviorBase
+{
+    /// <summary>
+    /// 
+    /// </summary>
+    /// <param name="disposable"></param>
+    protected override void OnAttachedToVisualTree(CompositeDisposable disposable)
+    {
+        var dispose = AssociatedObject?
+            .AddDisposableHandler(
+                InputElement.LostFocusEvent,
+                AssociatedObject_LostFocus,
+                RoutingStrategies.Tunnel | RoutingStrategies.Bubble);
+
+        if (dispose is not null)
+        {
+            disposable.Add(dispose);
+        }
+    }
+
+    private void AssociatedObject_LostFocus(object? sender, RoutedEventArgs e)
+    {
+        if (e.Handled)
+        {
+            return;
+        }
+
+        if (ExecuteCommand())
+        {
+            e.Handled = true;
+        }
+    }
+}