Add support for drag images and drop descriptions

src/System.Windows.Forms.Primitives/src/Interop/Interop.CLSID.cs

@@ -9,6 +9,9 @@ internal static class CLSID
         // 00BB2763-6A77-11D0-A535-00C04FD7D062
         internal static Guid AutoComplete = new Guid(0x00BB2763, 0x6A77, 0x11D0, 0xA5, 0x35, 0x00, 0xC0, 0x4F, 0xD7, 0xD0, 0x62);
 
+        // 4657278A-411B-11D2-839A-00C04FD918D0
+        internal static Guid DragDropHelper = new Guid(0x4657278A, 0x411B, 0x11D2, 0x83, 0x9A, 0x0, 0xC0, 0x4F, 0xD9, 0x18, 0xD0);
+
         // C0B4E2F3-BA21-4773-8DBA-335EC946EB8B
         internal static Guid FileSaveDialog = new Guid(0xC0B4E2F3, 0xBA21, 0x4773, 0x8D, 0xBA, 0x33, 0x5E, 0xC9, 0x46, 0xEB, 0x8B);
 

src/System.Windows.Forms.Primitives/src/Interop/Ole32/Interop.IDropSourceNotify.cs

@@ -0,0 +1,24 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Runtime.InteropServices;
+
+internal partial class Interop
+{
+    internal static partial class Ole32
+    {
+        [ComImport]
+        [Guid("0000012B-0000-0000-C000-000000000046")]
+        [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+        public interface IDropSourceNotfiy
+        {
+            [PreserveSig]
+            HRESULT DragEnterTarget(
+                IntPtr hwndTarget);
+
+            [PreserveSig]
+            HRESULT DragLeaveTarget();
+        }
+    }
+}

src/System.Windows.Forms.Primitives/src/Interop/Ole32/Interop.OleDuplicateData.cs

@@ -0,0 +1,15 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Runtime.InteropServices;
+using static Interop.Kernel32;
+
+internal static partial class Interop
+{
+    internal static partial class Ole32
+    {
+        [DllImport(Libraries.Ole32, ExactSpelling = true)]
+        public static extern IntPtr OleDuplicateData(IntPtr hSrc, short cfFormat, GMEM uiFlags);
+    }
+}

src/System.Windows.Forms.Primitives/src/Interop/Shell32/Interop.DROPDESCRIPTION.cs

@@ -0,0 +1,47 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Runtime.InteropServices;
+
+internal partial class Interop
+{
+    internal static partial class Shell32
+    {
+        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
+        public unsafe struct DROPDESCRIPTION
+        {
+            private DROPIMAGETYPE _type;
+            private fixed char _szMessage[Kernel32.MAX_PATH];
+            private fixed char _szInsert[Kernel32.MAX_PATH];
+
+            private Span<char> szMessage
+            {
+                get { fixed (char* c = _szMessage) { return new Span<char>(c, Kernel32.MAX_PATH); } }
+            }
+
+            private Span<char> szInsert
+            {
+                get { fixed (char* c = _szInsert) { return new Span<char>(c, Kernel32.MAX_PATH); } }
+            }
+
+            public DROPIMAGETYPE Type
+            {
+                get => _type;
+                set => _type = value;
+            }
+
+            public ReadOnlySpan<char> Message
+            {
+                get => szMessage.SliceAtFirstNull();
+                set => SpanHelpers.CopyAndTerminate(value, szMessage);
+            }
+
+            public ReadOnlySpan<char> Insert
+            {
+                get => szInsert.SliceAtFirstNull();
+                set => SpanHelpers.CopyAndTerminate(value, szInsert);
+            }
+        }
+    }
+}

src/System.Windows.Forms.Primitives/src/Interop/Shell32/Interop.DROPIMAGETYPE.cs

@@ -0,0 +1,21 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+internal partial class Interop
+{
+    internal static partial class Shell32
+    {
+        public enum DROPIMAGETYPE
+        {
+            DROPIMAGE_INVALID = -1,
+            DROPIMAGE_NONE = 0,
+            DROPIMAGE_COPY = 1,
+            DROPIMAGE_MOVE = 2,
+            DROPIMAGE_LINK = 4,
+            DROPIMAGE_LABEL = 6,
+            DROPIMAGE_WARNING = 7,
+            DROPIMAGE_NOIMAGE = 8
+        }
+    }
+}

src/System.Windows.Forms.Primitives/src/Interop/Shell32/Interop.IDragSourceHelper2.cs

@@ -0,0 +1,31 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Drawing;
+using System.Runtime.InteropServices;
+using System.Runtime.InteropServices.ComTypes;
+
+internal static partial class Interop
+{
+    internal static partial class Shell32
+    {
+        [ComImport]
+        [Guid("DE5BF786-477A-11D2-839D-00C04FD918D0")]
+        [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+        public interface IDragSourceHelper2
+        {
+            HRESULT InitializeFromBitmap(
+                SHDRAGIMAGE pshdi,
+                IDataObject dataObject);
+
+            HRESULT InitializeFromWindow(
+                IntPtr hwnd,
+                Point ppt,
+                IDataObject dataObject);
+
+            HRESULT SetFlags(
+                int dwFlags);
+        }
+    }
+}

src/System.Windows.Forms.Primitives/src/Interop/Shell32/Interop.IDropTargetHelper.cs

@@ -0,0 +1,46 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Drawing;
+using System.Runtime.InteropServices;
+using IComDataObject = System.Runtime.InteropServices.ComTypes.IDataObject;
+
+internal static partial class Interop
+{
+    internal static partial class Shell32
+    {
+        [ComImport]
+        [Guid("4657278B-411B-11D2-839A-00C04FD918D0")]
+        [InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
+        public interface IDropTargetHelper
+        {
+            [PreserveSig]
+            HRESULT DragEnter(
+                IntPtr hwndTarget,
+                [MarshalAs(UnmanagedType.Interface)]
+                IComDataObject pDataObj,
+                ref Point ppt,
+                uint dwEffect);
+
+            [PreserveSig]
+            HRESULT DragLeave();
+
+            [PreserveSig]
+            HRESULT DragOver(
+                ref Point ppt,
+                uint dwEffect);
+
+            [PreserveSig]
+            HRESULT Drop(
+                [MarshalAs(UnmanagedType.Interface)]
+                IComDataObject pDataObj,
+                ref Point ppt,
+                uint dwEffect);
+
+            [PreserveSig]
+            HRESULT Show(
+                BOOL fShow);
+        }
+    }
+}

src/System.Windows.Forms.Primitives/src/Interop/Shell32/Interop.SHDRAGIMAGE.cs

@@ -0,0 +1,22 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Drawing;
+using System.Runtime.InteropServices;
+using static Interop.Gdi32;
+
+internal partial class Interop
+{
+    internal static partial class Shell32
+    {
+        [StructLayout(LayoutKind.Sequential)]
+        public struct SHDRAGIMAGE
+        {
+            public Size sizeDragImage;
+            public Point ptOffset;
+            public HBITMAP hbmpDragImage;
+            public COLORREF crColorKey;
+        }
+    }
+}

src/System.Windows.Forms/src/PublicAPI.Unshipped.txt

@@ -3,3 +3,28 @@ System.Windows.Forms.LinkArea.Equals(System.Windows.Forms.LinkArea other) -> boo
 System.Windows.Forms.TableLayoutPanelCellPosition.Equals(System.Windows.Forms.TableLayoutPanelCellPosition other) -> bool
 override System.Windows.Forms.Form.OnGotFocus(System.EventArgs! e) -> void
 ~override System.Windows.Forms.ToolStripDropDownMenu.CreateAccessibilityInstance() -> System.Windows.Forms.AccessibleObject
+System.Windows.Forms.DropImageType
+System.Windows.Forms.DropImageType.Invalid = -1 -> System.Windows.Forms.DropImageType
+System.Windows.Forms.DropImageType.None = 0 -> System.Windows.Forms.DropImageType
+System.Windows.Forms.DropImageType.Copy = 1 -> System.Windows.Forms.DropImageType
+System.Windows.Forms.DropImageType.Move = 2 -> System.Windows.Forms.DropImageType
+System.Windows.Forms.DropImageType.Link = 4 -> System.Windows.Forms.DropImageType
+System.Windows.Forms.DropImageType.Label = 6 -> System.Windows.Forms.DropImageType
+System.Windows.Forms.DropImageType.Warning = 7 -> System.Windows.Forms.DropImageType
+System.Windows.Forms.DropImageType.NoImage = 8 -> System.Windows.Forms.DropImageType
+~System.Windows.Forms.Control.DoDragDrop(object data, System.Windows.Forms.DragDropEffects allowedEffects, System.Drawing.Bitmap dragImage, System.Drawing.Point cursorOffset, bool useDefaultDragImage) -> System.Windows.Forms.DragDropEffects
+~System.Windows.Forms.ToolStripItem.DoDragDrop(object data, System.Windows.Forms.DragDropEffects allowedEffects, System.Drawing.Bitmap dragImage, System.Drawing.Point cursorOffset, bool useDefaultDragImage) -> System.Windows.Forms.DragDropEffects
+System.Windows.Forms.DragEventArgs.DragEventArgs(System.Windows.Forms.IDataObject? data, int keyState, int x, int y, System.Windows.Forms.DragDropEffects allowedEffect, System.Windows.Forms.DragDropEffects effect, System.Windows.Forms.DropImageType dropImageType, string! message, string! messageReplacementToken) -> void
+System.Windows.Forms.DragEventArgs.DropImageType.get -> System.Windows.Forms.DropImageType
+System.Windows.Forms.DragEventArgs.DropImageType.set -> void
+System.Windows.Forms.DragEventArgs.Message.get -> string?
+System.Windows.Forms.DragEventArgs.Message.set -> void
+System.Windows.Forms.DragEventArgs.MessageReplacementToken.get -> string?
+System.Windows.Forms.DragEventArgs.MessageReplacementToken.set -> void
+System.Windows.Forms.GiveFeedbackEventArgs.GiveFeedbackEventArgs(System.Windows.Forms.DragDropEffects effect, bool useDefaultCursors, System.Drawing.Bitmap! dragImage, System.Drawing.Point cursorOffset, bool useDefaultDragImage) -> void
+System.Windows.Forms.GiveFeedbackEventArgs.CursorOffset.get -> System.Drawing.Point
+System.Windows.Forms.GiveFeedbackEventArgs.CursorOffset.set -> void
+System.Windows.Forms.GiveFeedbackEventArgs.DragImage.get -> System.Drawing.Bitmap!
+System.Windows.Forms.GiveFeedbackEventArgs.DragImage.set -> void
+System.Windows.Forms.GiveFeedbackEventArgs.UseDefaultDragImage.get -> bool
+System.Windows.Forms.GiveFeedbackEventArgs.UseDefaultDragImage.set -> void

src/System.Windows.Forms/src/System/Windows/Forms/Control.cs

@@ -5292,8 +5292,19 @@ internal virtual void DisposeAxControls()
         /// </summary>
         public DragDropEffects DoDragDrop(object data, DragDropEffects allowedEffects)
         {
-            Ole32.IDropSource dropSource = new DropSource(this);
+            return DoDragDrop(data, allowedEffects, dragImage: null, cursorOffset: default, useDefaultDragImage: false);
+        }
 
+        /// <summary>
+        ///  Begins a drag operation. The allowedEffects determine which
+        ///  drag operations can occur. If the drag operation needs to interop
+        ///  with applications in another process, data should either be
+        ///  a base managed class (String, Bitmap, or Metafile) or some Object
+        ///  that implements System.Runtime.Serialization.ISerializable. data can also be any Object that
+        ///  implements System.Windows.Forms.IDataObject.
+        /// </summary>
+        public DragDropEffects DoDragDrop(object data, DragDropEffects allowedEffects, Bitmap dragImage, Point cursorOffset, bool useDefaultDragImage)
+        {
             IComDataObject dataObject = null;
 
             if (data is IComDataObject)
@@ -5316,10 +5327,23 @@ public DragDropEffects DoDragDrop(object data, DragDropEffects allowedEffects)
                 dataObject = (IComDataObject)iwdata;
             }
 
-            HRESULT hr = Ole32.DoDragDrop(dataObject, dropSource, (Ole32.DROPEFFECT)allowedEffects, out Ole32.DROPEFFECT finalEffect);
-            if (!hr.Succeeded())
+            Ole32.DROPEFFECT finalEffect;
+
+            try
             {
-                return DragDropEffects.None;
+                Ole32.IDropSource dropSource = new DropSource(this, dataObject, dragImage, cursorOffset, useDefaultDragImage);
+                HRESULT hr = Ole32.DoDragDrop(dataObject, dropSource, (Ole32.DROPEFFECT)allowedEffects, out finalEffect);
+                if (!hr.Succeeded())
+                {
+                    return DragDropEffects.None;
+                }
+            }
+            finally
+            {
+                if (DragDropHelper.GetInDragLoop(dataObject))
+                {
+                    DragDropHelper.SetInDragLoop(dataObject, false);
+                }
             }
 
             return (DragDropEffects)finalEffect;

src/System.Windows.Forms/src/System/Windows/Forms/DataObject.cs

@@ -562,6 +562,19 @@ void IComDataObject.GetData(ref FORMATETC formatetc, out STGMEDIUM medium)
                 converter.OleDataObject.GetData(ref formatetc, out medium);
                 return;
             }
+            else if (_innerData is IDataObject dataObject && DragDropHelper.GetInDragLoop(dataObject))
+            {
+                medium = new STGMEDIUM();
+                string formatName = DataFormats.GetFormat(formatetc.cfFormat).Name;
+                Debug.WriteLineIf(CompModSwitches.DataObject.TraceVerbose, $"  InDragLoop {formatName}");
+                if (dataObject.GetDataPresent(formatName) && dataObject.GetData(formatName) is DragDropFormat dragDropFormat)
+                {
+                    medium = dragDropFormat.GetData();
+                    Debug.WriteLineIf(CompModSwitches.DataObject.TraceVerbose, $"    drag-and-drop private format retrieved {formatName}");
+                }
+
+                return;
+            }
 
             medium = new STGMEDIUM();
 
@@ -670,6 +683,23 @@ void IComDataObject.SetData(ref FORMATETC pFormatetcIn, ref STGMEDIUM pmedium, b
                 converter.OleDataObject.SetData(ref pFormatetcIn, ref pmedium, fRelease);
                 return;
             }
+            else if (_innerData is IDataObject dataObject
+                && (DragDropHelper.GetInDragLoopFormat(pFormatetcIn) || DragDropHelper.GetInDragLoop(dataObject)))
+            {
+                string formatName = DataFormats.GetFormat(pFormatetcIn.cfFormat).Name;
+                Debug.WriteLineIf(CompModSwitches.DataObject.TraceVerbose, $" InDragLoop {formatName}");
+                if (dataObject.GetDataPresent(formatName) && dataObject.GetData(formatName) is DragDropFormat dragDropFormat)
+                {
+                    dragDropFormat.RefreshData(pFormatetcIn.cfFormat, pmedium, fRelease);
+                }
+                else
+                {
+                    dataObject.SetData(formatName, new DragDropFormat(pFormatetcIn.cfFormat, pmedium, fRelease));
+                    Debug.WriteLineIf(CompModSwitches.DataObject.TraceVerbose, $"   drag-and-drop private format loaded {formatName}");
+                }
+
+                return;
+            }
 
             throw new NotImplementedException();
         }