how to use menuBar and Action

[sax94]

hy,
I saw on the nokia developer site that to connect a signal to a slot you should use connect(sender, SIGNAL(signal), receiver, SLOT(slot));
in my case this sould be

QObject::connect(ui->actionModifica_valore_iniziale,SIGNAL(triggered()),dialog,SLOT(show()));

QObject::connect(ui->actionModifica_valore_iniziale,SIGNAL(triggered()),dialog,SLOT(show()));

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so my menuFile Modifica_valore_iniziale that stands for set value, emits the signall triggered(). in the receiver spot I must put what I want to see wuen the signal is emitted, but if I put dialog Qt tells me that dialog wasn't declared, but if I put ui.menuBar and then I click the action the menuBar appears, same if I put ui.menuFile, the menuFile stays there. so what do I have to do?
thank's for the help