How to show thw widget in center?

[sudhansu]

Hi All
i've a dialog of size 401,431. I want to display it in the centre of my screen. But its showing at different position in different systems. (may be because of the different resolution ). How to achive it.
in constructor, I did like

this->move(QApplication::desktop()->screenGeometry().center());

this->move(QApplication::desktop()->screenGeometry().center());

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But its not working.
Plz help.