引言: 你要的是這個嗎? StringGrid1.Selection

procedure TForm1.Button9Click(Sender: TObject);
var
    I,J,R : Integer;
begin
    R := 0;
    for i:= 0 to StringGrid1.ColCount - 1 do
        begin
            for j := 0 to StringGrid1.RowCount - 1 do
                begin
                    If ((I >= StringGrid1.Selection.Left) and
                        (I <= StringGrid1.Selection.Right) and
                        (J >= StringGrid1.Selection.Top) and
                        (J <= StringGrid1.Selection.Bottom)) THEN
                        BEGIN
                          StringGrid1.Cells[I,J] := 'O';
                          Inc(r);
                        END
                    ELSE
                      StringGrid1.Cells[I,J] := 'X';
                end;
        end;
    ShowMessage(IntToStr(R)    ' cells had been selected !!')
end;

 
procedure TForm1.Button2Click(Sender: TObject);
var
 CellCount: Integer;
begin
  with StringGrid1.Selection do
    CellCount := (Right-Left 1)*(Bottom-Top 1);
  ShowMessage(IntToStr(CellCount));
end;