Create CCW for IDropSource

Progress towards dotnet#5163 and dotnet#4649
kant2002 · Feb 23, 2022 · 196b93b · 196b93b
1 parent 2646981
commit 196b93b
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Showing 4 changed files with 74 additions and 1 deletion.
diff --git a/src/System.Windows.Forms.Primitives/src/Interop/Interop.IID.cs b/src/System.Windows.Forms.Primitives/src/Interop/Interop.IID.cs
@@ -12,6 +12,9 @@ internal static class IID
         // EAC04BC0-3791-11D2-BB95-0060977B464C
         public static Guid IAutoComplete2 { get; } = new(0xEAC04BC0, 0x3791, 0x11D2, 0xBB, 0x95, 0x00, 0x60, 0x97, 0x7B, 0x46, 0x4C);
 
+        // 00000121-0000-0000-C000-000000000046
+        public static Guid IDropSource { get; } = new(0x00000121, 0x0000, 0x0000, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x46);
+
         // 00000101-0000-0000-C000-000000000046
         public static Guid IEnumString { get; } = new(0x00000101, 0x0000, 0x0000, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x46);
 

diff --git a/src/System.Windows.Forms.Primitives/src/Interop/Ole32/Interop.DoDragDrop.cs b/src/System.Windows.Forms.Primitives/src/Interop/Ole32/Interop.DoDragDrop.cs
@@ -12,8 +12,18 @@ internal static partial class Ole32
         [DllImport(Libraries.Ole32, ExactSpelling = true)]
         public static extern HRESULT DoDragDrop(
             IDataObject pDataObj,
-            IDropSource pDropSource,
+            IntPtr pDropSource,
             DROPEFFECT dwOKEffects,
             out DROPEFFECT pdwEffect);
+
+        public static HRESULT DoDragDrop(
+            IDataObject pDataObj,
+            IDropSource pDropSource,
+            DROPEFFECT dwOKEffects,
+            out DROPEFFECT pdwEffect)
+        {
+            var dropSourcePtr = WinFormsComWrappers.Instance.GetOrCreateComInterfaceForObject(pDropSource, CreateComInterfaceFlags.None);
+            return DoDragDrop(pDataObj, dropSourcePtr, dwOKEffects, out pdwEffect);
+        }
     }
 }
diff --git a/src/System.Windows.Forms.Primitives/src/Interop/WinFormsComWrappers.IDropSourceVtbl.cs b/src/System.Windows.Forms.Primitives/src/Interop/WinFormsComWrappers.IDropSourceVtbl.cs
@@ -0,0 +1,41 @@
+// 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.CompilerServices;
+using System.Runtime.InteropServices;
+
+internal partial class Interop
+{
+    internal unsafe partial class WinFormsComWrappers
+    {
+        internal static class IDropSourceVtbl
+        {
+            public static IntPtr Create(IntPtr fpQueryInterface, IntPtr fpAddRef, IntPtr fpRelease)
+            {
+                IntPtr* vtblRaw = (IntPtr*)RuntimeHelpers.AllocateTypeAssociatedMemory(typeof(IDropSourceVtbl), IntPtr.Size * 5);
+                vtblRaw[0] = fpQueryInterface;
+                vtblRaw[1] = fpAddRef;
+                vtblRaw[2] = fpRelease;
+                vtblRaw[3] = (IntPtr)(delegate* unmanaged<IntPtr, BOOL, User32.MK, HRESULT>)&QueryContinueDrag;
+                vtblRaw[4] = (IntPtr)(delegate* unmanaged<IntPtr, Ole32.DROPEFFECT, HRESULT>)&GiveFeedback;
+
+                return (IntPtr)vtblRaw;
+            }
+
+            [UnmanagedCallersOnly]
+            private static HRESULT QueryContinueDrag(IntPtr thisPtr, BOOL fEscapePressed, User32.MK grfKeyState)
+            {
+                var inst = ComInterfaceDispatch.GetInstance<Ole32.IDropSource>((ComInterfaceDispatch*)thisPtr);
+                return inst.QueryContinueDrag(fEscapePressed, grfKeyState);
+            }
+
+            [UnmanagedCallersOnly]
+            private static HRESULT GiveFeedback(IntPtr thisPtr, Ole32.DROPEFFECT dwEffect)
+            {
+                var inst = ComInterfaceDispatch.GetInstance<Ole32.IDropSource>((ComInterfaceDispatch*)thisPtr);
+                return inst.GiveFeedback(dwEffect);
+            }
+        }
+    }
+}
diff --git a/src/System.Windows.Forms.Primitives/src/Interop/WinFormsComWrappers.cs b/src/System.Windows.Forms.Primitives/src/Interop/WinFormsComWrappers.cs
@@ -21,6 +21,7 @@ internal unsafe partial class WinFormsComWrappers : ComWrappers
         private static readonly ComInterfaceEntry* s_streamEntry = InitializeIStreamEntry();
         private static readonly ComInterfaceEntry* s_fileDialogEventsEntry = InitializeIFileDialogEventsEntry();
         private static readonly ComInterfaceEntry* s_enumStringEntry = InitializeIEnumStringEntry();
+        private static readonly ComInterfaceEntry* s_dropSourceEntry = InitializeIDropSourceEntry();
 
         internal static WinFormsComWrappers Instance { get; } = new WinFormsComWrappers();
 
@@ -62,6 +63,18 @@ private WinFormsComWrappers() { }
             return wrapperEntry;
         }
 
+        private static ComInterfaceEntry* InitializeIDropSourceEntry()
+        {
+            GetIUnknownImpl(out IntPtr fpQueryInterface, out IntPtr fpAddRef, out IntPtr fpRelease);
+
+            IntPtr iDropSourceVtbl = IDropSourceVtbl.Create(fpQueryInterface, fpAddRef, fpRelease);
+
+            ComInterfaceEntry* wrapperEntry = (ComInterfaceEntry*)RuntimeHelpers.AllocateTypeAssociatedMemory(typeof(WinFormsComWrappers), sizeof(ComInterfaceEntry));
+            wrapperEntry->IID = IID.IDropSource;
+            wrapperEntry->Vtable = iDropSourceVtbl;
+            return wrapperEntry;
+        }
+
         protected override unsafe ComInterfaceEntry* ComputeVtables(object obj, CreateComInterfaceFlags flags, out int count)
         {
             if (obj is Interop.Ole32.IStream)
@@ -76,6 +89,12 @@ private WinFormsComWrappers() { }
                 return s_fileDialogEventsEntry;
             }
 
+            if (obj is Ole32.IDropSource)
+            {
+                count = 1;
+                return s_dropSourceEntry;
+            }
+
             if (obj is IEnumString)
             {
                 count = 1;