CTreeCtrl disable drag and drop on specific nodes

Question

I there a way to disable drag and drop on specific nodes of a CTreeCtrl?

I would like to prevent dragging a node to a child of that same node within the same tree, and also to prevent dragging a node to a listview that is linked to the same node or one of it's children.

Answer 1

It just depends on how you handle the drop target in the mouse move handler.

You can not prevent the TVN_BEGINDRAG function. But if the item shouldn't be dragged at all, you always use SetDropTarget(NULL) in the mouse move handler and if dragging stops you do nothing.

When the item is allowed to be dragged, you just need to check if the target is allowed. You use HitTest to find the target item and you can check if it is allowed to drop here. Again use SetDropTarget. So the user can see what is allowed.

Another way would be to implement the Ole Drag&Drop functions like in this sample here.