Don't unwrap wrapped DataObject inner data store (#12800)

When creating a DataObject from another DataObject we need to keep the original DataObject as the "inner" data so that virtuals get called as they historically have.

Also pass through to correct overload on TryGetDataCore.

Fixes #12789

Author: JeremyKuhne

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

@@ -45,11 +45,7 @@ public DataObject()
     /// </summary>
     public DataObject(object data)
     {
-        if (data is DataObject dataObject)
-        {
-            _innerData = dataObject._innerData;
-        }
-        else if (data is IDataObject iDataObject)
+        if (data is IDataObject iDataObject)
         {
             _innerData = Composition.CreateFromWinFormsDataObject(iDataObject);
         }

src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/ClipboardTests.cs

@@ -699,4 +699,33 @@ public void Clipboard_SetDataObject_Text()
         byte[] array = stream.ToArray();
         array.Should().BeEquivalentTo("Hello, World!\0"u8.ToArray());
     }
+
+    [WinFormsFact]
+    public void Clipboard_DerivedDataObject_DataPresent()
+    {
+        // https://github.com/dotnet/winforms/issues/12789
+        SomeDataObject data = new();
+
+        // This was provided as a workaround for the above and should not break, but should
+        // also work without it.
+        data.SetData(SomeDataObject.Format, data);
+
+        Clipboard.SetDataObject(data);
+        Clipboard.ContainsData(SomeDataObject.Format).Should().BeTrue();
+        Clipboard.GetDataObject()!.GetDataPresent(SomeDataObject.Format).Should().BeTrue();
+
+        data = new();
+        Clipboard.SetDataObject(data);
+        Clipboard.ContainsData(SomeDataObject.Format).Should().BeTrue();
+        Clipboard.GetDataObject()!.GetDataPresent(SomeDataObject.Format).Should().BeTrue();
+    }
+
+    public class SomeDataObject : DataObject
+    {
+        public static string Format => "SomeDataObjectId";
+        public override string[] GetFormats() => [Format];
+
+        public override bool GetDataPresent(string format, bool autoConvert)
+            => format == Format || base.GetDataPresent(format, autoConvert);
+    }
 }

src/System.Windows.Forms/tests/UnitTests/System/Windows/Forms/DataObjectTests.cs

@@ -2657,4 +2657,77 @@ public unsafe void DataObject_ComTypesIDataObject_MockRoundTrip_IsWrapped()
         IDataObject outData = dropTargetAccessor.CreateDelegate<CreateWinFormsDataObjectForOutgoingDropData>()(inDataPtr);
         outData.Should().BeSameAs(inData);
     }
+
+    [Fact]
+    public void DataObject_CreateFromDataObject_DoesNotUnwrapDataStore()
+    {
+        // The inner data should not have it's data store unwrapped.
+        DataObject dataObject = new();
+        DataObject wrapped = new(dataObject);
+        DataObject.Composition composition = wrapped.TestAccessor().Dynamic._innerData;
+        IDataObject original = composition.TestAccessor().Dynamic._winFormsDataObject;
+        original.Should().BeSameAs(dataObject);
+    }
+
+    [Fact]
+    public void DataObject_CreateFromDataObject_VirtualsAreCalled()
+    {
+        Mock<DataObject> mock = new(MockBehavior.Loose);
+        DataObject wrapped = new(mock.Object);
+
+        wrapped.GetData("Foo", false);
+        mock.Verify(o => o.GetData("Foo", false), Times.Once());
+        mock.VerifyNoOtherCalls();
+        mock.Reset();
+
+        wrapped.GetData("Foo");
+        mock.Verify(o => o.GetData("Foo", true), Times.Once());
+        mock.VerifyNoOtherCalls();
+        mock.Reset();
+
+        wrapped.GetData(typeof(string));
+        mock.Verify(o => o.GetData("System.String", true), Times.Once());
+        mock.VerifyNoOtherCalls();
+        mock.Reset();
+
+        wrapped.GetDataPresent("Foo", false);
+        mock.Verify(o => o.GetDataPresent("Foo", false), Times.Once());
+        mock.VerifyNoOtherCalls();
+        mock.Reset();
+
+        wrapped.GetDataPresent("Foo");
+        mock.Verify(o => o.GetDataPresent("Foo", true), Times.Once());
+        mock.VerifyNoOtherCalls();
+        mock.Reset();
+
+        wrapped.GetDataPresent(typeof(string));
+        mock.Verify(o => o.GetDataPresent("System.String", true), Times.Once());
+        mock.VerifyNoOtherCalls();
+        mock.Reset();
+
+        wrapped.GetFormats(false);
+        mock.Verify(o => o.GetFormats(false), Times.Once());
+        mock.VerifyNoOtherCalls();
+        mock.Reset();
+
+        wrapped.GetFormats();
+        mock.Verify(o => o.GetFormats(true), Times.Once());
+        mock.VerifyNoOtherCalls();
+        mock.Reset();
+
+        wrapped.SetData("Foo", "Bar");
+        mock.Verify(o => o.SetData("Foo", "Bar"), Times.Once());
+        mock.VerifyNoOtherCalls();
+        mock.Reset();
+
+        wrapped.SetData(typeof(string), "Bar");
+        mock.Verify(o => o.SetData(typeof(string), "Bar"), Times.Once());
+        mock.VerifyNoOtherCalls();
+        mock.Reset();
+
+        wrapped.SetData("Bar");
+        mock.Verify(o => o.SetData("Bar"), Times.Once());
+        mock.VerifyNoOtherCalls();
+        mock.Reset();
+    }
 }