title: Loading page in WPF
body: <p>Guys, I have a basic WPF application. Contains App.xaml as always and a Mainwindow.xaml.
  I've created also some pages like page1/2/3. I want to load for example page1.xaml in mainwindow.xaml. Is this possible? And also want to close it so the content of mainwindow.xaml will stay in there.</p>
  
  <p>I dont want this to be a navigation application with the left/right arrows at the top.</p>