[RC1] Implement Platform Args for Drag and Drop EventArgs

src/Compatibility/Core/src/iOS/DragAndDropDelegate.cs

@@ -147,8 +147,9 @@ public UIDragItem[] HandleDragStarting(View element, IVisualElementRenderer rend
 
 				if (args.Cancel)
 					return;
-
+#pragma warning disable CS0618 // Type or member is obsolete
 				if (!args.Handled)
+#pragma warning restore CS0618 // Type or member is obsolete
 				{
 					UIImage uIImage = null;
 					string clipDescription = String.Empty;

src/Controls/samples/Controls.Sample.UITests/Elements/DragAndDropEventArgs.xaml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentView xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             AutomationId="DragAndDropEventArgs"
+             x:Class="Maui.Controls.Sample.DragAndDropEventArgs">
+    <StackLayout>
+        <StackLayout Orientation="Horizontal">
+            <Label HeightRequest="200" WidthRequest="200" AutomationId="LabelDragElement"
+                   Text="Drag me Over the Purple Box, off the purple box, drop me on the purple box, and then verify all the correct events fired">
+                <Label.GestureRecognizers>
+                    <DragGestureRecognizer DragStarting="DragStarting" DropCompleted="DropCompleted"></DragGestureRecognizer>
+                </Label.GestureRecognizers>
+            </Label>
+            <Label HeightRequest="200" HorizontalOptions="FillAndExpand" Background="Purple" AutomationId="DragTarget">
+                <Label.GestureRecognizers>
+                    <DropGestureRecognizer DragLeave="DragLeave" DragOver="DragOver" Drop="Drop"></DropGestureRecognizer>
+                </Label.GestureRecognizers>
+            </Label>
+        </StackLayout>
+        <Label x:Name="events" AutomationId="DragEventsLabel" Text="EventsLabel">
+            <Label.GestureRecognizers>
+                <DropGestureRecognizer></DropGestureRecognizer>
+            </Label.GestureRecognizers>
+        </Label>
+    </StackLayout>
+</ContentView>

src/Controls/samples/Controls.Sample.UITests/Elements/DragAndDropEventArgs.xaml.cs

@@ -0,0 +1,151 @@
+using Microsoft.Maui.Controls;
+using Microsoft.Maui.Controls.Xaml;
+
+namespace Maui.Controls.Sample;
+
+[XamlCompilation(XamlCompilationOptions.Compile)]
+public partial class DragAndDropEventArgs : ContentView
+{
+	bool _emittedDragOver = false;
+	public DragAndDropEventArgs()
+	{
+		InitializeComponent();
+	}
+
+	void AddEvent(string name)
+	{
+		events.Text += $"{name},";
+	}
+
+	void DragStarting(object sender, DragStartingEventArgs e)
+	{
+		_emittedDragOver = false;
+		if (e.PlatformArgs is PlatformDragStartingEventArgs platformArgs)
+		{
+#if IOS || MACCATALYST
+			if (platformArgs.Sender is not null)
+				AddEvent("DragStarting:" + nameof(platformArgs.Sender));
+			if (platformArgs.DragInteraction is not null)
+				AddEvent("DragStarting:" + nameof(platformArgs.DragInteraction));
+			if (platformArgs.DragSession is not null)
+				AddEvent("DragStarting:" + nameof(platformArgs.DragSession));
+#elif ANDROID
+			if (platformArgs.Sender is not null)
+				AddEvent("DragStarting:" + nameof(platformArgs.Sender));
+			if (platformArgs.MotionEvent is not null)
+				AddEvent("DragStarting:" + nameof(platformArgs.MotionEvent));
+#elif WINDOWS
+			if (platformArgs.Sender is not null)
+				AddEvent("DragStarting:" + nameof(platformArgs.Sender));
+			if (platformArgs.DragStartingEventArgs is not null)
+				AddEvent("DragStarting:" + nameof(platformArgs.DragStartingEventArgs));
+			AddEvent("DragStarting:" + nameof(platformArgs.Handled));
+#endif
+		}
+	}
+
+	void DropCompleted(object sender, DropCompletedEventArgs e)
+	{
+		if (e.PlatformArgs is PlatformDropCompletedEventArgs platformArgs)
+		{
+#if IOS || MACCATALYST
+			if (platformArgs.Sender is not null)
+				AddEvent("DropCompleted:" + nameof(platformArgs.Sender));
+			if (platformArgs.DropInteraction is not null)
+				AddEvent("DropCompleted:" + nameof(platformArgs.DropInteraction));
+			if (platformArgs.DropSession is not null)
+				AddEvent("DropCompleted:" + nameof(platformArgs.DropSession));
+#elif ANDROID
+			if (platformArgs.Sender is not null)
+				AddEvent("DropCompleted:" + nameof(platformArgs.Sender));
+			if (platformArgs.DragEvent is not null)
+				AddEvent("DropCompleted:" + nameof(platformArgs.DragEvent));
+#elif WINDOWS
+			if (platformArgs.Sender is not null)
+				AddEvent("DropCompleted:" + nameof(platformArgs.Sender));
+			if (platformArgs.DropCompletedEventArgs is not null)
+				AddEvent("DropCompleted:" + nameof(platformArgs.DropCompletedEventArgs));
+#endif
+		}
+	}
+
+	void DragLeave(object sender, DragEventArgs e)
+	{
+		if (e.PlatformArgs is PlatformDragEventArgs platformArgs)
+		{
+#if IOS || MACCATALYST
+			if (platformArgs.Sender is not null)
+				AddEvent("DragLeave:" + nameof(platformArgs.Sender));
+			if (platformArgs.DropInteraction is not null)
+				AddEvent("DragLeave:" + nameof(platformArgs.DropInteraction));
+			if (platformArgs.DropSession is not null)
+				AddEvent("DragLeave:" + nameof(platformArgs.DropSession));
+#elif ANDROID
+			if (platformArgs.Sender is not null)
+				AddEvent("DragLeave:" + nameof(platformArgs.Sender));
+			if (platformArgs.DragEvent is not null)
+				AddEvent("DragLeave:" + nameof(platformArgs.DragEvent));
+#elif WINDOWS
+			if (platformArgs.Sender is not null)
+				AddEvent("DragLeave:" + nameof(platformArgs.Sender));
+			if (platformArgs.DragEventArgs is not null)
+				AddEvent("DragLeave:" + nameof(platformArgs.DragEventArgs));
+			AddEvent("DragLeave:" + nameof(platformArgs.Handled));
+#endif
+		}
+	}
+
+	void DragOver(object sender, DragEventArgs e)
+	{
+		if (!_emittedDragOver) // This can generate a lot of noise, only add it once
+		{
+			if (e.PlatformArgs is PlatformDragEventArgs platformArgs)
+			{
+#if IOS || MACCATALYST
+				if (platformArgs.Sender is not null)
+					AddEvent("DragOver:" + nameof(platformArgs.Sender));
+				if (platformArgs.DropInteraction is not null)
+					AddEvent("DragOver:" + nameof(platformArgs.DropInteraction));
+				if (platformArgs.DropSession is not null)
+					AddEvent("DragOver:" + nameof(platformArgs.DropSession));
+#elif ANDROID
+				if (platformArgs.Sender is not null)
+					AddEvent("DragOver:" + nameof(platformArgs.Sender));
+				if (platformArgs.DragEvent is not null)
+					AddEvent("DragOver:" + nameof(platformArgs.DragEvent));
+#elif WINDOWS
+				if (platformArgs.Sender is not null)
+					AddEvent("DragOver:" + nameof(platformArgs.Sender));
+				if (platformArgs.DragEventArgs is not null)
+					AddEvent("DragOver:" + nameof(platformArgs.DragEventArgs));
+#endif
+			}
+			_emittedDragOver = true;
+		}
+	}
+
+	void Drop(object sender, DropEventArgs e)
+	{
+		if (e.PlatformArgs is PlatformDropEventArgs platformArgs)
+		{
+#if IOS || MACCATALYST
+			if (platformArgs.Sender is not null)
+				AddEvent("Drop:" + nameof(platformArgs.Sender));
+			if (platformArgs.DropInteraction is not null)
+				AddEvent("Drop:" + nameof(platformArgs.DropInteraction));
+			if (platformArgs.DropSession is not null)
+				AddEvent("Drop:" + nameof(platformArgs.DropSession));
+#elif ANDROID
+			if (platformArgs.Sender is not null)
+				AddEvent("Drop:" + nameof(platformArgs.Sender));
+			if (platformArgs.DragEvent is not null)
+				AddEvent("Drop:" + nameof(platformArgs.DragEvent));
+#elif WINDOWS
+			if (platformArgs.Sender is not null)
+				AddEvent("Drop:" + nameof(platformArgs.Sender));
+			if (platformArgs.DragEventArgs is not null)
+				AddEvent("Drop:" + nameof(platformArgs.DragEventArgs));
+#endif
+		}
+	}
+}

src/Controls/samples/Controls.Sample.UITests/Elements/DragAndDropGallery.cs

@@ -9,6 +9,7 @@ public DragAndDropGallery()
 		{
 			Add(new DragAndDropEvents());
 			Add(new DragAndDropBetweenLayouts());
+			Add(new DragAndDropEventArgs());
 		}
 	}
 }

src/Controls/src/Core/DragAndDrop/DragEventArgs.cs

@@ -13,9 +13,19 @@ public DragEventArgs(DataPackage dataPackage)
 			AcceptedOperation = DataPackageOperation.Copy;
 		}
 
+		internal DragEventArgs(DataPackage dataPackage, PlatformDragEventArgs platformArgs) : this(dataPackage)
+		{
+			PlatformArgs = platformArgs;
+		}
+
 		/// <include file="../../../docs/Microsoft.Maui.Controls/DragEventArgs.xml" path="//Member[@MemberName='Data']/Docs/*" />
 		public DataPackage Data { get; }
 		/// <include file="../../../docs/Microsoft.Maui.Controls/DragEventArgs.xml" path="//Member[@MemberName='AcceptedOperation']/Docs/*" />
 		public DataPackageOperation AcceptedOperation { get; set; }
+
+		/// <summary>
+		/// Gets the platform-specific arguments associated with the <see cref="DragEventArgs"/>.
+		/// </summary>
+		public PlatformDragEventArgs PlatformArgs { get; }
 	}
 }

src/Controls/src/Core/DragAndDrop/DragGestureRecognizer.cs

@@ -90,19 +90,16 @@ internal void SendDropCompleted(DropCompletedEventArgs args)
 			DropCompleted?.Invoke(this, args);
 		}
 
-		internal DragStartingEventArgs SendDragStarting(IView element)
+		internal DragStartingEventArgs SendDragStarting(IView element, PlatformDragStartingEventArgs platformArgs = null)
 		{
-			var args = new DragStartingEventArgs();
+			var args = new DragStartingEventArgs(platformArgs);
 
 			DragStartingCommand?.Execute(DragStartingCommandParameter);
 			DragStarting?.Invoke(this, args);
 
-			if (!args.Handled)
-			{
-				args.Data.PropertiesInternal.Add("DragSource", element);
-			}
+			args.Data.PropertiesInternal.Add("DragSource", element);
 
-			if (args.Cancel || args.Handled)
+			if (args.Cancel)
 				return args;
 
 			_isDragActive = true;

src/Controls/src/Core/DragAndDrop/DragStartingEventArgs.cs

@@ -12,11 +12,22 @@ public DragStartingEventArgs()
 			Data = new DataPackage();
 		}
 
+		internal DragStartingEventArgs(PlatformDragStartingEventArgs platformArgs) : this()
+		{
+			PlatformArgs = platformArgs;
+		}
+
 		/// <include file="../../../docs/Microsoft.Maui.Controls/DragStartingEventArgs.xml" path="//Member[@MemberName='Handled']/Docs/*" />
+		[Obsolete("Use PlatformArgs to handle customization. On Windows, set the PlatformArgs.Handled property to true if changing DragStartingEventArgs.")]
 		public bool Handled { get; set; }
 		/// <include file="../../../docs/Microsoft.Maui.Controls/DragStartingEventArgs.xml" path="//Member[@MemberName='Cancel']/Docs/*" />
 		public bool Cancel { get; set; }
 		/// <include file="../../../docs/Microsoft.Maui.Controls/DragStartingEventArgs.xml" path="//Member[@MemberName='Data']/Docs/*" />
 		public DataPackage Data { get; private set; }
+
+		/// <summary>
+		/// Gets the platform-specific arguments associated with the <see cref="DragStartingEventArgs"/>.
+		/// </summary>
+		public PlatformDragStartingEventArgs PlatformArgs { get; }
 	}
 }

src/Controls/src/Core/DragAndDrop/DropCompletedEventArgs.cs

@@ -1,4 +1,3 @@
-#nullable disable
 using System;
 
 namespace Microsoft.Maui.Controls
@@ -7,5 +6,22 @@ namespace Microsoft.Maui.Controls
 	public class DropCompletedEventArgs : EventArgs
 	{
 		DataPackageOperation DropResult { get; }
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="DropCompletedEventArgs"/> class.
+		/// </summary>
+		public DropCompletedEventArgs()
+		{
+		}
+
+		internal DropCompletedEventArgs(PlatformDropCompletedEventArgs platformArgs) : this()
+		{
+			PlatformArgs = platformArgs;
+		}
+
+		/// <summary>
+		/// Gets the platform-specific arguments associated with the <see cref="DropCompletedEventArgs"/>.
+		/// </summary>
+		public PlatformDropCompletedEventArgs? PlatformArgs { get; }
 	}
 }

src/Controls/src/Core/DragAndDrop/DropEventArgs.cs

@@ -13,9 +13,20 @@ public DropEventArgs(DataPackageView view)
 			Data = view;
 		}
 
+		internal DropEventArgs(DataPackageView view, PlatformDropEventArgs platformArgs) : this(view)
+		{
+			PlatformArgs = platformArgs;
+		}
+
 		/// <include file="../../../docs/Microsoft.Maui.Controls/DropEventArgs.xml" path="//Member[@MemberName='Data']/Docs/*" />
 		public DataPackageView Data { get; }
+
 		/// <include file="../../../docs/Microsoft.Maui.Controls/DropEventArgs.xml" path="//Member[@MemberName='Handled']/Docs/*" />
 		public bool Handled { get; set; }
+
+		/// <summary>
+		/// Gets the platform-specific arguments associated with the <see cref="DropEventArgs"/>.
+		/// </summary>
+		public PlatformDropEventArgs PlatformArgs { get; }
 	}
 }