fix: Fix sender argument in Window events and x:Bind in Window when i…

…t's root of XAML

src/SourceGenerators/Uno.UI.SourceGenerators/XamlGenerator/XamlFileGenerator.cs

@@ -1001,6 +1001,8 @@ private void BuildCompiledBindingsInitializer(IndentedStringBuilder writer, INam
 				IsType(_xClassName.Symbol, frameworkElementSymbol)              // The current type may not have a base type as it is defined in XAML,
 				|| IsType(controlBaseType, frameworkElementSymbol);    // so look at the control base type extracted from the XAML.
 
+			var isWindow = IsWindow(controlBaseType);
+
 			if (hasXBindExpressions || hasResourceExtensions)
 			{
 				var activator = _isHotReloadEnabled
@@ -1010,15 +1012,19 @@ private void BuildCompiledBindingsInitializer(IndentedStringBuilder writer, INam
 				writer.AppendLineIndented($"Bindings = {activator};");
 			}
 
-			if (isFrameworkElement && (hasXBindExpressions || hasResourceExtensions))
+			if ((isFrameworkElement || isWindow) && (hasXBindExpressions || hasResourceExtensions))
 			{
 				if (_isHotReloadEnabled)
 				{
 					// Attach the current context to itself to avoid having a closure in the lambda
 					writer.AppendLineIndented($"global::Uno.UI.Helpers.MarkupHelper.SetElementProperty(__that, \"owner\", __that);");
 				}
 
-				using (writer.BlockInvariant($"Loading += (s, e) => "))
+				var eventSubscription = isFrameworkElement
+					? "Loading += (s, e) =>"
+					: "Activated += (s, e) =>";
+
+				using (writer.BlockInvariant(eventSubscription))
 				{
 					if (_isHotReloadEnabled && _xClassName.Symbol != null)
 					{

src/Uno.UI.RuntimeTests/Tests/BindingTests/BindingTests.cs

@@ -6,6 +6,7 @@
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Automation;
 using Microsoft.UI.Xaml.Controls;
+using SamplesApp.UITests;
 using Uno.UI.RuntimeTests.Helpers;
 
 namespace Uno.UI.RuntimeTests.Tests;
@@ -49,4 +50,22 @@ public async Task When_BindingShouldBeAppliedOnPropertyChangedEvent()
 		Assert.AreEqual(2, converter.ConvertCount);
 		Assert.AreEqual("1", SUT.myTb.Text);
 	}
+
+	[TestMethod]
+	[UnoWorkItem("https://github.com/unoplatform/uno/issues/16520")]
+	public async Task When_XBind_In_Window()
+	{
+		var SUT = new XBindInWindow();
+		SUT.Activate();
+		try
+		{
+			Assert.AreEqual(0, SUT.ClickCount);
+			SUT.MyButton.AutomationPeerClick();
+			Assert.AreEqual(1, SUT.ClickCount);
+		}
+		finally
+		{
+			SUT.Close();
+		}
+	}
 }

src/Uno.UI.RuntimeTests/Tests/BindingTests/XBindInWindow.xaml

@@ -0,0 +1,13 @@
+<Window
+    x:Class="Uno.UI.RuntimeTests.Tests.XBindInWindow"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:local="using:Uno.UI.RuntimeTests.Tests"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d">
+
+    <Grid>
+		<Button Click="{x:Bind Click}" x:Name="MyButton" x:FieldModifier="public" />
+    </Grid>
+</Window>

src/Uno.UI.RuntimeTests/Tests/BindingTests/XBindInWindow.xaml.cs

@@ -0,0 +1,18 @@
+using Microsoft.UI.Xaml;
+
+namespace Uno.UI.RuntimeTests.Tests;
+
+public sealed partial class XBindInWindow : Window
+{
+	public int ClickCount { get; private set; }
+
+	public XBindInWindow()
+	{
+		this.InitializeComponent();
+	}
+
+	public void Click(object sender, RoutedEventArgs args)
+	{
+		ClickCount++;
+	}
+}

src/Uno.UI/UI/Xaml/Window/Implementations/BaseWindowImplementation.cs

@@ -118,7 +118,7 @@ protected void InitializeNativeWindow()
 
 	private void OnNativeShown(object? sender, EventArgs e) => ContentManager.TryLoadRootVisual(XamlRoot!);
 
-	private void OnNativeClosed(object? sender, EventArgs args) => Closed?.Invoke(this, new WindowEventArgs());
+	private void OnNativeClosed(object? sender, EventArgs args) => Closed?.Invoke(Window, new WindowEventArgs());
 
 	private void OnNativeSizeChanged(object? sender, Size size)
 	{
@@ -145,7 +145,7 @@ private void OnNativeSizeChanged(object? sender, Size size)
 #if !HAS_UNO_WINUI // CoreWindow has a different WindowSizeChangedEventArgs type, let's skip raising it completely.
 		CoreWindow?.OnSizeChanged(coreWindowSizeChangedEventArgs);
 #endif
-		SizeChanged?.Invoke(this, windowSizeChanged);
+		SizeChanged?.Invoke(Window, windowSizeChanged);
 
 		XamlRoot?.RaiseChangedEvent();
 	}
@@ -174,7 +174,7 @@ private void OnNativeVisibilityChanged(object? sender, bool isVisible)
 		var args = new VisibilityChangedEventArgs() { Visible = isVisible };
 
 		CoreWindow?.OnVisibilityChanged(args);
-		VisibilityChanged?.Invoke(this, args);
+		VisibilityChanged?.Invoke(Window, args);
 		SystemThemeHelper.RefreshSystemTheme();
 	}
 
@@ -211,7 +211,7 @@ private void OnActivationStateChanged(CoreWindowActivationState state)
 		var coreWindowActivatedEventArgs = activatedEventArgs;
 #endif
 		CoreWindow?.OnActivated(coreWindowActivatedEventArgs);
-		Activated?.Invoke(this, activatedEventArgs);
+		Activated?.Invoke(Window, activatedEventArgs);
 		SystemThemeHelper.RefreshSystemTheme();
 	}