WPF Navigation

How to navigate from window.xam to page.xaml in wpf using C# code on button click??

I am struggling with with this from last 3 days??

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private void Ok_Click(object sender, RoutedEventArgs e)

{

// Page2 p = new Page2();

//p.NavigationService.Navigate(this);

// NavigationService nav = NavigationService.GetNavigationService(this);

//nav.Navigate(new System.Uri("Page2.xaml", UriKind.RelativeOrAbsolute));

//Page2 p2 = new Page2();

//nav.Navigate(p2);

// Window obj = new Window();

//_mainFrame.NavigationService.Navigate(new Page2());

////_mainFrame.Navigate(new Page2());

}