Clipboard.SetDataObject method regression in .NET 9.0.100-rc.2

[akhromushkin]

Description

Clipboard.SetDataObject method doesn't place a custom DataObject into the clipboard.

Reproduction Steps

1. Create a .NET Framework WinForms (or WPF) project.
2. Create a custom DataObject class descendant:

    public class SomeDataObject : DataObject {
        public static string Format = "SomeDataObjectId";
        public override string[] GetFormats() {
            return new string[] { Format };
        }
    }

3. Call the Clipboard.SetDataObject(new SomeDataObject()); method to add the SomeDataObject's class instance into the clipboard.

Expected behavior

SomeDataObject is added into the clipboard

And Clipboard.GetDataObject().GetDataPresent(SomeDataObject.Format) is true

Actual behavior

The clipboard doesn't contain the SomeDataObject instance

And Clipboard.GetDataObject().GetDataPresent(SomeDataObject.Format) is false

Regression?

Yes, in .NET 8 everything works.

Known Workarounds

No response

Impact

No response

Configuration

$ dotnet --info
.NET SDK:
 Version:           9.0.100-rc.2.24474.11
 Commit:            315e1305db
 Workload version:  9.0.100-manifests.4872d5d5
 MSBuild version:   17.12.0-preview-24473-03+fea15fbd1

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.22631
 OS Platform: Windows
 RID:         win-x64
 Base Path:   C:\Program Files\dotnet\sdk\9.0.100-rc.2.24474.11\

Host:
  Version:      9.0.0-rc.2.24473.5
  Architecture: x64
  Commit:       990ebf52fc

.NET SDKs installed:
  9.0.100-rc.2.24474.11 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 9.0.0-rc.2.24474.3 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 9.0.0-rc.2.24473.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 9.0.0-rc.2.24474.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other information

No response

[miloush]

Please include a repro project. This seems like an unusual way to use data objects. Perhaps the regression is because of the binary formatter removal? https://devblogs.microsoft.com/dotnet/binaryformatter-removed-from-dotnet-9/.

[Kuldeep-MS]

@akhromushkin After following your reproduction steps, I encountered the error shown below. Could you please provide more detailed steps?

[akhromushkin]

Perhaps is more related to WinForms. So I have attached several projects:
Issue_10049_WPF.zip
Issue_10049_WinForms.zip

[BlueBSH]

This issue still exists in the RTM GA version of .NET9.0.0

[miloush]

This is all Winforms classes and should be moved to the Winforms repo.

[JeremyKuhne]

The WPF repro given is actually using the WinForms Clipboard class. You can't derive the DataObject class in System.Windows.

I'm not seeing this with the latest fix for the Clipboard, but haven't root caused it yet.

@lonitra fyi