fix(Bindings): Avoid propagating DataContext if you are not the child…

…'s parent

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml_Controls/Given_Flyout.cs

@@ -4,13 +4,15 @@
 using System.Threading.Tasks;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 using Private.Infrastructure;
+using Uno.Extensions;
 using Uno.UI.Extensions;
 using Uno.UI.RuntimeTests.Extensions;
 using Uno.UI.RuntimeTests.Helpers;
 using Windows.UI;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Controls.Primitives;
+using Windows.UI.Xaml.Data;
 using Windows.UI.Xaml.Media;
 
 namespace Uno.UI.RuntimeTests.Tests.Windows_UI_Xaml_Controls
@@ -231,6 +233,33 @@ public async Task When_Attached_To_TextBlock_Check_Placement()
 			}
 		}
 
+		[TestMethod]
+		[RunsOnUIThread]
+		public async Task Test_Flyout_Binding()
+		{
+#if IS_UNO
+			var (flyout, content) = CreateFlyoutWithBinding();
+
+			var buttonA = new Button()
+			{
+				Content = "Button A",
+				Flyout = flyout,
+				DataContext = "My Data Context",
+			};
+
+			TestServices.WindowHelper.WindowContent = buttonA;
+
+			await TestServices.WindowHelper.WaitForLoaded(buttonA);
+
+			buttonA.RaiseClick();
+
+			await TestServices.WindowHelper.WaitForLoaded(content);
+
+			var stackPanel = content as StackPanel;
+			Assert.AreEqual("My Data Context", (stackPanel.Children[0] as TextBlock).Text);
+#endif
+		}
+
 		private static void VerifyRelativeContentPosition(HorizontalPosition horizontalPosition, VerticalPosition verticalPosition, FrameworkElement content, double minimumTargetOffset, Border target)
 		{
 			var contentScreenBounds = content.GetOnScreenBounds();
@@ -290,6 +319,30 @@ private static void VerifyRelativeContentPosition(HorizontalPosition horizontalP
 			return (flyout, content);
 		}
 
+		private (Flyout Flyout, FrameworkElement Content) CreateFlyoutWithBinding()
+		{
+
+			var flyout = new Flyout
+			{
+				FlyoutPresenterStyle = GetSimpleFlyoutPresenterStyle()
+			};
+
+			var content = new StackPanel
+			{
+				Children =
+				{
+					new TextBlock().Apply(x => x.SetBinding(TextBlock.TextProperty, new Binding())),
+					new Button
+					{
+						Content = "Button B",
+					}.Apply(x => x.SetBinding(Button.CommandParameterProperty, new Binding() { Source = flyout }))
+				}
+			};
+
+			flyout.Content = content;
+			return (flyout, content);
+		}
+
 		private static Style GetSimpleFlyoutPresenterStyle() => new Style
 		{
 			TargetType = typeof(FlyoutPresenter),

src/Uno.UI.Tests/DependencyProperty/Given_DependencyProperty.DataContext.cs

@@ -230,7 +230,7 @@ public void When_DataContext_Inherited_And_Child_Removed()
 			Assert.AreEqual(null, SUT.DataContext);
 			Assert.AreEqual(0, parentCtxChanged);
 			Assert.AreEqual(1, SUTCtxChanged);
-			Assert.AreEqual(1, childCtxChanged);
+			Assert.AreEqual(0, childCtxChanged);
 		}
 
 		[TestMethod]

src/Uno.UI/UI/Xaml/DependencyObjectStore.Binder.cs

@@ -105,10 +105,21 @@ void SetInherited(IDependencyObjectStoreProvider provider)
 					provider.Store.SetInheritedDataContext(inheritedValue);
 				}
 			}
-
 			for (int i = 0; i < _childrenBindable.Count; i++)
 			{
 				var child = _childrenBindable[i];
+				var parent = child?.GetParent();
+
+				//Do not propagate value if you are not this child's parent
+				//Covers case where a child may hold a binding to a view higher up the tree
+				//Example: Button A contains a Flyout with Button B inside of it
+				//	Button B has a binding to the Flyout itself
+				//	We should not propagate Button B's DataContext to the Flyout
+				//	since its real parent is actually Button A 
+				if (parent != null && parent != ActualInstance)
+				{
+					continue;
+				}
 
 				if (child is IDependencyObjectStoreProvider provider)
 				{