More trimming friendly DragDrop

Currently DragDrop process starts with DragDropEffects DoDragDrop(object data, DragDropEffects allowedEffects) which inside perform dispatcherization of the supported interfaces and objects. Sometimes this may means that we rely on Built-in COM support for cast of the interfaces.

Built-in COM support maybe disabled in modern .NET and do not supported in NativeAOT flavor of CoreCLR. I propose provide API which put responsibility of AOT supported casting on the consumer side by introducing typed version of the method.

public class Control
{
+ [BuiltInComDragonsHere]
  public DragDropEffects DoDragDrop(object data, DragDropEffects allowedEffects)
+ public DragDropEffects DoDragDrop(System.Runtime.InteropServices.ComTypes.IDataObject data, DragDropEffects allowedEffects)
+ public DragDropEffects DoDragDrop(System.Windows.Forms.IDataObject data, DragDropEffects allowedEffects)
}
public class ToolStripItem
{
+ [BuiltInComDragonsHere]
  public DragDropEffects DoDragDrop(object data, DragDropEffects allowedEffects)
+ public DragDropEffects DoDragDrop(System.Runtime.InteropServices.ComTypes.IDataObject data, DragDropEffects allowedEffects)
+ public DragDropEffects DoDragDrop(System.Windows.Forms.IDataObject data, DragDropEffects allowedEffects)
}

This would be considered source breaking change.

/cc @weltkante since you maybe interested in giving feedback on this.

[JeremyKuhne]

@kant2002 sorry, I’m not clear on how that helps. @AaronRobinsonMSFT are there resources on built-in COM and trimming? All I really know at this point is that we should be moving away from ComImport where possible, but I don’t even really know why. 😃

[RussKie]

The team will discuss in one of the upcoming triages.