Open a QMainWindow Object in QDialog Object

[chuengchuenghq]

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,

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

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

To copy to clipboard, switch view to plain text mode 

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


thank for u all.