In The MouseDown event for the control where the drag will begin, use the DoDragDrop method to kaş the data to be dragged and the allowed effect dragging will have. For more information, see Data and AllowedEffect. The convincing argument in #3201 for this to be separate event is that https://www.csharpegitimi.com.tr/2024/05/csharp-mouse-click-kullanimi.html