Скопировать/переместить содержимое одной выделенной ячейки в другую

//---------------------------------------------------------------------------
void __fastcall TForm1::StringGrid1MouseDown(TObject *Sender,
      TMouseButton Button, TShiftState Shift, int X, int Y)
{
    StringGrid1->BeginDrag(0,-1);
}
//---------------------------------------------------------------------------
void __fastcall TForm1::StringGrid1DragOver(TObject *Sender,
      TObject *Source, int X, int Y, TDragState State, bool &Accept)
{
     Accept = 1;
}
//---------------------------------------------------------------------------
void __fastcall TForm1::StringGrid1DragDrop(TObject *Sender,
      TObject *Source, int X, int Y)
{
    int cd = StringGrid1->DefaultColWidth,
        rd = StringGrid1->DefaultRowHeight,
        co = ((TStringGrid*)Source)->Col,
        ro = ((TStringGrid*)Source)->Row;
    StringGrid1->Cells[X/cd][Y/rd] = StringGrid1->Cells[co][ro];
}
//---------------------------------------------------------------------------

void __fastcall TForm1::StringGrid1DragDrop(TObject *Sender,
      TObject *Source, int X, int Y)
{
    int co = ((TStringGrid*)Source)->Col,
        ro = ((TStringGrid*)Source)->Row,   acol , arow;
    StringGrid1->MouseToCell(X,Y,acol,arow);
    String So = StringGrid1->Cells[co][ro];
    String Ta = StringGrid1->Cells[acol][arow];
    StringGrid1->Cells[acol][arow] = So;
    StringGrid1->Cells[co][ro] = Ta;
}