how to chage frame page in page itself (wpf)?

See more:

WPF

Hi Friends,

In my wpf window left side one tree view and right side frame is there. if i chang the tree view item the frame loaded related pages. now the page is contain one exit button.

if i click exit button, that page should close and default page occupy in frame.

i was try some code but its not giving solution. help me.

private void btn_Exit_Click(object sender, RoutedEventArgs e)
       {
           frame1.Source = new System.Uri("non.xaml", UriKind.Relative);
       }

in this code was correctly work in window. but page it throw frame1 not in the current content error ,..

then i try

NavigationService.Navigate("non.xaml");

.

but it only open a new page.

how to code for this.?.