function CheckRowDrag(var Origin, Destination: Integer; const MousePt: TPoint): Boolean; dynamic;
DYNAMIC bool __fastcall CheckRowDrag(int &Origin, int &Destination, const System::Types::TPoint &MousePt);
CheckRowDrag validates whether the row currently selected for dragging can be dropped at the current location.
Use CheckRowDrag to validate that the row currently selected for dragging can be dropped at the current location. CheckRowDrag can change the Origin (the row being dragged) and/or the Destination (the drop target), as needed, to keep the grid's rows in order.