按鍵上下鍵變成下一個物件去

procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word;
Shift: TShiftState);
begin
  case Key of
    VK_DOWN: Perform(WM_NEXTDLGCTL, 0, 0);
    VK_UP: Perform(WM_NEXTDLGCTL, 1, 0);
  end;
end;