procedure TForm1.StringGrid1SelectCell(Sender: TObject; ACol,
ARow: Integer; var CanSelect: Boolean);
begin
if trim(stringgrid1.Cells[FCol,FRow])='' then
begin
CanSelect:=false;
StringGrid1.Row :=FRow;
StringGrid1.Col :=FCol;
StringGrid1.SetFocus;
end
else
begin
FRow:=ARow;
FCol:=ACol;
end;