Support IDragSourceHelper/IDragTargetHelper?

These two interfaces are used to support enhanced drag-and-drop support, including (most importantly for me) the ability to specify a custom image to be displayed under the cursor during the drag. While this can be done in C# today by using COM interop, you have to roll your own IDataObject implementation to do so, as the default Windows Forms one does not support setting arbitrary COM-based private formats into the data object, per Windows requirements. Would it be possible to update the Windows Forms DataObject class to enable this? (It would be even better if there would be higher-level code added to obviate the need to do custom COM interop to use thesee features, but I do not know what the API design for that would look like.) Thanks!

[willibrandon]

Hi @wjk - We added support for drag images and drop descriptions, available since .NET 7 RC1. A sample program can be found here.

The drag image and drop description will be displayed if DragEventArgs.DropImageType is set to a value greater than DropImageType.Invalid. The drag image bitmap can be specified using the Control.DoDragDrop(Object, DragDropEffects, Bitmap, Point, Boolean) method or by setting GiveFeedbackEventArgs.DragImage property during the Control.GiveFeedback event.

Please let me know if you get a chance to test it and if so, any feedback is appreciated. Thanks.

[dreddy-work]

We have similar proposal for drag events showing underlying image here: https://github.com/dotnet/winforms/pull/6576.