WPF拖放DragDropEffects更改离开WPF窗口时的效果

Question

I have a WPF application where I'm dragging an file object around. It can be dropped either into several windows inside of the application, or externally into Explorer and onto the desktop and a few other places.

The drag and drop operation works fine, but the DragDropEffect only shows properly inside of the application Window. When the cursor moves outside of the App window I get the 'verboten' icon - most of the time. Depending on how the cursor leaves the app most of the time I get the slashed out circle. But sometimes it correctly continues dragging with the copy icon.

var files = new[] {editor.MarkdownDocument.Filename} ;
var dragData = new DataObject(DataFormats.FileDrop,files);

DragDrop.DoDragDrop(tab, dragData, DragDropEffects.Copy);

As mentioned the code and the handling by the shell works properly - the file is copied, it's only the drag icon that's the problem.

I can control the drag icon inside of the application, no problem on the window, but I have no control what happens outside of it.

So how do I control the drag icon reliably external to WPF?

Answer 1

https://docs.microsoft.com/en-us/dotnet/api/system.windows.dragdrop.givefeedback

DragDrop.GiveFeedback += SetTheCursorHere;

You should (per Microsoft's documentation) cache the cursor, etc. because it's called over and over again while dragging, and you don't want to LoadResource as the drag occurs.