Coloring Cells in a StringGrid / DBGrid

Problem/Question/Abstract:

StringGrids / DBGrids with colored cells looks very nice and you can inform the user about importent data inside the Grid.

Answer:

Unfortunately you can't use the same method for coloring StringGrids and DBGrids. So first let's have a look to the StringGrid:

1. StringGrid

Use the "OnDrawCell"-event to make your StringGrids colorful! The following Code shows how to give your Grid a red background color. The second column will be colored with green background.

procedure TForm1.StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;
  Rect: TRect; State: TGridDrawState);

const //define your color here. Of course you
  //can use default colors too.
  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;

But now lets coloring DBGrids:

2. DBGrid

It's much easier to give color to DBGrids. Here you have to use the "OnDrawColumnCell"-Event. The following example is coloring the Cells of Column "Status" when the value is not "a".
If you want to color the whole line you only have to delete the "If..." statement (see below)

procedure TForm1.DBGrid1DrawColumnCell(Sender: TObject; const Rect: TRect;
  DataCol: Integer; Column: TColumn;
  State: TGridDrawState);
const
  clPaleGreen = TColor($CCFFCC);
  clPaleRed = TColor($CCCCFF);
begin

  if Column.FieldName = 'Status' then //Remove this line, if you want
    //to highlight the whole line

    if Column.Field.Dataset.FieldbyName('Status').AsString <> 'a' then
      if (gdFocused in State) {//does the cell have the focus? } then
        dbgrid1.canvas.brush.color := clBlack //focused
      else
        dbgrid1.canvas.brush.color := clPaleGreen; //not focused

  //Now let's paint the cell using a Default-Method:
  dbgrid1.DefaultDrawColumnCell(rect, DataCol, Column, State)
end;