Opening page in frame C#?

Question

C++ / C#

I created a frame form, in it a button in which the page that I created for frame should open.
Navigation is simple.

private void MainWindow_OnLoaded(object sender, RoutedEventArgs e)
{
if (Page1 == null)
Page1 = new Page1();
this.Frame.Navigate(Page1);
}

I placed a frame on the form, and when certain buttons are pressed, it should open my pages in the frame, but I can’t understand what I’m doing wrong.
There are no examples on the internet.

Answer 1

What is the problem?