Revision 1 of 2, by Jwdietrich on 4-5-2023. The page as it is now.

TDrawGrid

TDrawGrid is a component on the Additional tab of the Component Palette. A DrawGrid provides a tabular display of graphical information. The developer is responsible for providing the code for drawing.

Therefore, unlike other grid types, TDrawGrid requires implementing the following properties:

OnDrawCell(Sender: TObject; aCol, aRow: Integer; aRect: TRect; aState: TGridDrawState): Handler for the basic cell painting event
DefaultDrawing: a boolean property deciding whether or not OnDrawCell has to handle the entire code for cell painting or if the default drawing mechanism is fired in addition.

The following simple example shows how to use OnDrawCell:

pascal

procedure TForm1.DrawGrid1DrawCell(Sender: TObject; aCol, aRow: Integer;
  aRect: TRect; aState: TGridDrawState);
var
  theCanvas: TCanvas;
begin
  theCanvas := TDrawGrid(Sender).Canvas;
  if odd(aRow) then
  begin
    if odd(aCol) then
      theCanvas.Brush.Color := clRed
    else
      theCanvas.Brush.Color := clGreen;
  end
  else
  begin
    if odd(aCol) then
      theCanvas.Brush.Color := clBlue
    else
      theCanvas.Brush.Color := clYellow;
  end;
  theCanvas.FillRect(aRect);
end;

The demonstration code in this example fills the content of the cells with different colours, depending on whether the rows or columns are even or odd:

<figure> <img src="TDrawGridExample.png" title="TDrawGridExample.png" /> <figcaption>TDrawGridExample.png</figcaption> </figure>

TDrawGrid

See also