Drag Drop With Confirmation Request

Hello, Pierre-Jean,    

I would like to note that RadTreeView handles the whole drag and drop operation by its TreeViewDragDropService. There is an appropriate public API that handles all aspects of the drag and drop operation. The PreviewDragOver event allows you to control on what targets the node element being dragged can be dropped on. The PreviewDragDrop event allows you to get a handle on all the aspects of the drag and drop operation, the source (drag) tree view, the destination (target) control, as well as the node being dragged. This is where we will initiate the actual physical move of the node(s) from one tree view to the target control. 

You can customize the drag and drop service and in the OnPreviewDragDrop method show the confirmation message and then decide what drop logic to be executed according to the user's choice. Please give it a try and see how it works on your end. A sample approach for customizing the TreeViewDragDropService is available in the following help article. You can use it as a starting point: https://docs.telerik.com/devtools/winforms/controls/treeview/drag-and-drop/drag-and-drop-in-bound-mode 

I hope this information helps. If you need any further assistance please don't hesitate to contact me. 

Regards,
Dess | Tech Support Engineer, Sr.
Progress Telerik