[Windows] - Handle Dynamic Updates for CanDrag and AllowDrop in Drag and Drop Gesture (dotnet#27845)

* Fixed-Drag-And-Drop-RunTime

* Modified-Test

* Reverted-test

* Modified-Code

* Reverted-Unwanted-Changes

* Modified.

Author: prakashKannanSf3972

src/Controls/src/Core/Platform/GestureManager/GesturePlatformManager.Windows.cs

@@ -406,6 +406,18 @@ void ClearContainerEventHandlers()
 					_container.ManipulationCompleted -= OnManipulationCompleted;
 					_container.PointerCanceled -= OnPointerCanceled;
 				}
+
+				if (Element is View && ElementGestureRecognizers is { } gestureRecognizers)
+				{
+					if (gestureRecognizers.FirstGestureOrDefault<DragGestureRecognizer>() is { } dragGesture)
+					{
+						dragGesture.PropertyChanged -= HandleDragAndDropGesturePropertyChanged;
+					}
+					if (gestureRecognizers.FirstGestureOrDefault<DropGestureRecognizer>() is { } dropGesture)
+					{
+						dropGesture.PropertyChanged -= HandleDragAndDropGesturePropertyChanged;
+					}
+				}
 			}
 		}
 
@@ -822,26 +834,36 @@ void UpdateDragAndDropGestureRecognizers()
 				return;
 			}
 
-			bool canDrag = gestures.FirstGestureOrDefault<DragGestureRecognizer>()?.CanDrag ?? false;
-			bool allowDrop = gestures.FirstGestureOrDefault<DropGestureRecognizer>()?.AllowDrop ?? false;
+			DragGestureRecognizer? dragGesture = gestures.FirstGestureOrDefault<DragGestureRecognizer>();
+			DropGestureRecognizer? dropGesture = gestures.FirstGestureOrDefault<DropGestureRecognizer>();
 
-			if (canDrag)
+			if (dragGesture is not null)
 			{
-				_subscriptionFlags |= SubscriptionFlags.ContainerDragEventsSubscribed;
+				dragGesture.PropertyChanged -= HandleDragAndDropGesturePropertyChanged;
+				dragGesture.PropertyChanged += HandleDragAndDropGesturePropertyChanged;
 
-				_container.CanDrag = true;
-				_container.DragStarting += HandleDragStarting;
-				_container.DropCompleted += HandleDropCompleted;
+				if (dragGesture.CanDrag && ((_subscriptionFlags & SubscriptionFlags.ContainerDragEventsSubscribed) == 0))
+				{
+					_subscriptionFlags |= SubscriptionFlags.ContainerDragEventsSubscribed;
+					_container.CanDrag = true;
+					_container.DragStarting += HandleDragStarting;
+					_container.DropCompleted += HandleDropCompleted;
+				}
 			}
 
-			if (allowDrop)
+			if (dropGesture is not null)
 			{
-				_subscriptionFlags |= SubscriptionFlags.ContainerDropEventsSubscribed;
+				dropGesture.PropertyChanged -= HandleDragAndDropGesturePropertyChanged;
+				dropGesture.PropertyChanged += HandleDragAndDropGesturePropertyChanged;
 
-				_container.AllowDrop = true;
-				_container.DragOver += HandleDragOver;
-				_container.Drop += HandleDrop;
-				_container.DragLeave += HandleDragLeave;
+				if (dropGesture.AllowDrop && ((_subscriptionFlags & SubscriptionFlags.ContainerDropEventsSubscribed) == 0))
+				{
+					_subscriptionFlags |= SubscriptionFlags.ContainerDropEventsSubscribed;
+					_container.AllowDrop = true;
+					_container.DragOver += HandleDragOver;
+					_container.Drop += HandleDrop;
+					_container.DragLeave += HandleDragLeave;
+				}
 			}
 		}
 
@@ -983,6 +1005,15 @@ void HandleDoubleTapped(object sender, DoubleTappedRoutedEventArgs doubleTappedR
 			doubleTappedRoutedEventArgs.Handled = true;
 		}
 
+		void HandleDragAndDropGesturePropertyChanged(object? sender, System.ComponentModel.PropertyChangedEventArgs e)
+		{
+			if (e.PropertyName == DragGestureRecognizer.CanDragProperty.PropertyName ||
+				e.PropertyName == DropGestureRecognizer.AllowDropProperty.PropertyName)
+			{
+				UpdateDragAndDropGestureRecognizers();
+			}
+		}
+
 		DragEventArgs ToDragEventArgs(UI.Xaml.DragEventArgs e, PlatformDragEventArgs platformArgs)
 		{
 			// The package should never be null here since the UI.Xaml.DragEventArgs have already been initialized

src/Controls/tests/TestCases.HostApp/Issues/Issue12726.cs

@@ -0,0 +1,61 @@
+namespace Maui.Controls.Sample.Issues
+{
+
+	[Issue(IssueTracker.Github, 12726, "Drag and Drop Gesture Fails on Runtime Changes of CanDrag and AllowDrop in Windows",
+		PlatformAffected.UWP)]
+	public class Issue12726 : TestContentPage
+	{
+		protected override void Init()
+		{
+			Label dragResult = new Label();
+			Label dropResult = new Label();
+
+			DragGestureRecognizer dragGestureRecognizer = new DragGestureRecognizer { CanDrag = false };
+			Label dragBox = new Label
+			{
+				HeightRequest = 200,
+				WidthRequest = 200,
+				BackgroundColor = Colors.Purple,
+				GestureRecognizers = { dragGestureRecognizer },
+				AutomationId = "DragElement"
+			};
+			dragGestureRecognizer.DragStarting += (_, __) => dragResult.Text = "DragEventTriggered";
+
+			DropGestureRecognizer dropGestureRecognizer = new DropGestureRecognizer { AllowDrop = false };
+			Label dropBox = new Label
+			{
+				HeightRequest = 200,
+				WidthRequest = 200,
+				BackgroundColor = Colors.Pink,
+				GestureRecognizers = { dropGestureRecognizer },
+				AutomationId = "DropTarget"
+			};
+			dropGestureRecognizer.Drop += (_, __) => dropResult.Text = "DropEventTriggered";
+
+			Button button = new Button
+			{
+				Text = "Enable Drag and Drop",
+				AutomationId = "EnableDragAndDrop"
+			};
+
+			button.Clicked += (_, __) =>
+			{
+				dragGestureRecognizer.CanDrag = true;
+				dropGestureRecognizer.AllowDrop = true;
+			};
+
+			Content = new StackLayout
+			{
+				Spacing = 5,
+				Children =
+				{
+					dragBox,
+					dropBox,
+					button,
+					dragResult,
+					dropResult
+				}
+			};
+		}
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue12726.cs

@@ -0,0 +1,25 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue12726 : _IssuesUITest
+	{
+		public Issue12726(TestDevice testDevice) : base(testDevice)
+		{
+		}
+
+		public override string Issue => "Drag and Drop Gesture Fails on Runtime Changes of CanDrag and AllowDrop in Windows";
+
+		[Test]
+		[Category(UITestCategories.DragAndDrop)]
+		public void DragAndDropShouldWorkRunTime()
+		{
+			App.WaitForElement("EnableDragAndDrop");
+			App.Tap("EnableDragAndDrop");
+			App.DragAndDrop("DragElement", "DropTarget");
+			App.WaitForElement("DragEventTriggered");
+		}
+	}
+}