add a Row Number in your DBGrid

{+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
1. create new blank field in dbgrid
2. rename the title with 'No'
3. put this code in OnDrawColumncell
4. Now your Grid has a row number
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++}

procedure TForm1.DBGrid1DrawColumnCell(Sender: TObject; const Rect: TRect;
DataCol: Integer; Column: TColumn; State: TGridDrawState);
begin
if DataSource1.DataSet.RecNo > 0 then
begin
if Column.Title.Caption = 'No' then
DBGrid1.Canvas.TextOut(Rect.Left + 2, Rect.Top, IntToStr(DataSource1.DataSet.RecNo));
end;
end;