I have a RichTextBox representing a program. It is enabled for Drag&Drop, items can be dragged around, and new items can be dragged to it. However some drop positions are invalid, so I?d like to change the cursor between DragDropEffects.None and DragDropEffects.Move, rather than just producing an error message (which is my interim solution).

I can calculate DropValid = True/False from the mouse position, but I can?t find an event to use this to do what I want. MouseMove doesn?t fire once a DragDrop has started, DragEnter fires only once, and a RichTextBox has no DragOver or similar event. So what do I do? RichTextBox doesn't enable GiveFeedback, so most of the posts that I have found don't seem applicable.

Any help gratefully accepted.
Robert.