How to add an event for the top-level menu

[fkfj]

@toolbar::toolbar....
{
action1 = new QAction(tr("open other.."),this);
menu *menuins=new menu(tr("open"),this);

    menuins->addAction(action1);
    addAction(menuins->menuAction());

   connect(menu??

}
@
Add a MENU in the toolbar , but the top-level menu can not capture the event