Open a QMainWindow Object in QDialog Object

I wanna open QMainWindow Object in QDialog Object:
in the login in dialog,as u see:
main dialog is a QDialog Object called frmlogin:
after close the main dialog,the QMainWindow called frmMain will appear.

this is the simply source,

Code:

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this->close();                // close the main dialog
frmMain mainwindow(this); 
mainwindow.show();   //show the QMainWindow

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as u see,The mainwindow never appear.How can i do to let it work well?


thank for u all.

in your qdialog

Code:

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connect (your_close_signal(maybe close button)), SIGNAL (clicked()),this , SLOT (show_frmmain()));
 
void yourdialog::show_frmmain()
{
	frmMain *calfrm = new frmMain;
	calfrm->show();
}

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this is only one of many possible answers try to explore! ;)