In The DragEnter event for the control where the drop will occur, ensure that the veri being dragged is of an acceptable type (in this case, Text). The code then sets the effect that will happen when the drop occurs to a value in the DragDropEffects enumeration. For more information, https://www.csharpegitimi.com.tr/2024/05/csharp-mouse-click-kullanimi.html