coloring stringgrid

   The StringGrid has propery DefaultDrawing.

   Set DefaultDrawing = False - for owner draw

After you set DefaultDrawing to False then try this code :

procedure TForm1.StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;
  Rect: TRect; State: TGridDrawState);
begin
  // set the font Bold and Red
  StringGrid1.Canvas.Font.Color := clRed;
  StringGrid1.Canvas.Font.Style := StringGrid1.Canvas.Font.Style + [fsBold];
  // draw the text in the cell
  StringGrid1.Canvas.TextOut (Rect.TopLeft.x, Rect.TopLeft.y,
                              StringGrid1.Cells[ACol, ARow]);
end;

procedure TForm1.StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;
  Rect: TRect; State: TGridDrawState);
const //define your color here.
  clPaleGreen = TColor($CCFFCC);
  clPaleRed = TColor($CCCCFF);

begin

  //Does the cell have the focus you have to paint it with other colors
  if (gdFocused in State) then
  begin
    StringGrid1.Canvas.Brush.Color := clBlack;
    StringGrid1.Canvas.Font.Color := clWhite;
  end
  else //Does the cell have NOT the focus you can use
    //your personal colors here
    if ACol = 2 //the second Column should be
    {//green, the other cells red } then
      StringGrid1.Canvas.Brush.color := clPaleGreen
    else
      StringGrid1.canvas.brush.Color := clPaleRed;

  //Now Paint the cells, but only, if the cell isn't the Title- Row/Column
  //This of course depends whether you have title-Row/Columns or not.

  if (ACol > 0) and (ARow > 0) then
  begin
    //Painting the Background
    StringGrid1.canvas.fillRect(Rect);

    //Painting the Text. Here you can improve the code with
    // using alignment and so on.
    StringGrid1.canvas.TextOut(Rect.Left, Rect.Top, StringGrid1.Cells[ACol, ARow]);
  end;
end;

If you want to colorize your cells depending on values in the cells you can replace the 3 lines (if Acol = 2 ......) with something like this

if StringGrid1.Cells[ACol, ARow] = 'highlight it' then
  StringGrid1.Canvas.Brush.color := clPalered
else
  StringGrid1.canvas.brush.Color := clwhite;