procedure TForm1.DBGridDrawDataCell(Sender:TObject; const Rect:TRect;  
  Field:TField; State:TGridDrawState);  
begin  
  if gdFocused in State then  
    with (Sender as TDBGrid).Canvas do  
      begin  
        Brush.Color := clRed;  
        FillRect(Rect);  
        TextOut(Rect.Left, Rect.Top, Field.AsString);  
      end;  
end;