title: How can I programmatically cancel a drag operation begun outside of a WPF app?
body: <p>I have a TreeView whose AllowDrop property is set to false but still shows the copy cursor when dragging a file over it. I've read about the QueryContinueDrag event but that seems to only fire when dragging things already on the object/form/whatever be around. I would like to cancel the drag operation i.e. return the cursor to normal and drop the file, when a user takes a file from outside the application (desktop, email attachment, etc) and brings it into the TreeView. Are there any ways I can do this? From what I can tell the QueryContinueDrag is the only event with an Arg that allows me to set the DragAction to "cancel" and it doesn't fire when bringing in outside files. I've also considering forcing an "esc" keypress or mouse right click but I don't want to use PIvoke.</p>