先設置form1.keypreview := TRUE:
procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
  Shift: TShiftState);
begin
    if Shift <> [] then Exit;
    case Key of
      VK_F2:
        if BtnAdd.CanFocus then
        begin
          BtnAdd.SetFocus;
          BtnAddClick(nil);
        end;      VK_F3:
        if BtnDel.CanFocus then
        begin
          BtnDel.SetFocus;
          BtnDelClick(nil);
        end;
    end;   
end;