Handle the NodeModified event, call view.ClientToDoc(view.PointToClient(MousePosition)) to get the mouse pointer position in the diagram coordinate system, and finally call GetLinkAt() to find out if there is a link there. Additionally, take a look Workflow Designer sample - it handles drag-and-drop of listbox items onto links.

I hope that helps,
Stoyan

You should not call DocToClient but ClientToDoc. The static Conrol.MousePosition property gives you the mouse location in screen coordinates. Calling view.PointToClient(MousePosition) returns the mouse coordinates relative to the view. Finally, ClientToDoc returns the document coordinates which you can pass to GetLinkAt.

I've just seen there is a MousePosition property of NodeEventArgs which should give you the mouse position directly in document coordinates, so you wouldn't need those conversions if you use it instead of Control.MousePosition.

I hope that helps,
Stoyan

You shouldn't have to do anything special to make it work with scrolling. NodeEventArgs.MousePosition returns the mouse position in diagram coordinates, relative to the top-left of the whole document. Same if you are using ClientToDoc - it applies both the scroll position and zoom factor values to the converted coordinates.

If you set Node.Obstacle = false, e.g. in the NodeStartModifying event handler, the links will not be re-routed when the node is dropped. Then you could set Obstacle back to true in the Modified event. Another way to do that is to temporarily set TriggerRerouting to Never.

I hope that helps,
Stoyan