function GridSelectAll(Grid: TDBGrid): Longint; begin Result := 0;
Grid.SelectedRows.Clear; with Grid.DataSource.DataSet do
begin First;
DisableControls; try
while not EOF do
begin Grid.SelectedRows.CurrentRowSelected := True;
Inc(Result);
Next; end; finally EnableControls; end; end; end;
procedure TForm1.Button1Click(Sender: TObject); begin GridSelectAll(DBGrid1); end;