Author: Tomas Rutkauskas

Using Delphi 4 and a TStringGrid component: How do I highlight the entire row in 
the grid where the cursor is currently? In other words, if the user clicks their 
mouse cursor on row 3, I want the entire row 3 to be highlighted pale yellow. When 
they then move the cursor to row 6, I want row 3 to revert back to white, and then 
have the entire row 6 turn pale yellow. Please note that I must be able to also 
edit the contents of any cell in the highlighted row.

Answer:

You can achieve this fairly easily with a combination of handlers for the 
OnSelectCell and OndrawCell events of the grid:

1   type
2     TGridCracker = class(TStringGrid);
3     {required to access protected method InvalidateRow}
4   
5   procedure TForm1.StringGrid1SelectCell(Sender: TObject; ACol, ARow: Integer;
6     var CanSelect: Boolean);
7   begin
8     with TGridCracker(Sender as TStringGrid) do
9     begin
10      InvalidateRow(Row);
11      InvalidateRow(aRow);
12    end;
13  end;
14  
15  procedure TForm1.StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;
16    Rect: TRect; State: TGridDrawState);
17  var
18    grid: TStringGrid;
19  begin
20    if gdFixed in State then
21      Exit;
22    grid := Sender as TStringGrid;
23    if grid.Row = aRow then
24    begin
25      with Grid.Canvas.Brush do
26      begin
27        Color := $C0FFFF; {pale yellow}
28        Style := bsSolid;
29      end;
30      grid.Canvas.FillRect(Rect);
31      grid.Canvas.Font.Color := clBlack;
32      grid.Canvas.TextRect(Rect, Rect.Left + 2, Rect.Top + 2, grid.Cells[acol, arow]);
33      Grid.Canvas.Brush := grid.Brush;
34    end;
35  end;