title: Navigation and Query parameter to another page Windows Phone 8.1
body: <p>I have Windows Phone 8.1 app and I need to navigate from a main page to page "pizdec" with parameteres. <p>
  I have a cod which can do it in WP8.0, but how car rewrite it in code WP8.1, I don't know.<p>
  Example:</p>
  
  <pre><code>private void listbox1_SelectionChanged(object sender, SelectionChangedEventArgs e)
     {
       if (listbox1.SelectedItem != null)
       {
          var file = listbox1.SelectedItem as StorageFile;
          NavigationService.Navigate(new Uri("/pizdec.xaml?filename=" + file.Name, UriKind.Relative));
          listbox1.SelectedItem = null;
       }
  </code></pre>
  
  <p>I know that I need use <code>this.Frame.Navigate()</code> , but I do not understand how to rewrite it to 8.1 
  <p>
  Code from <code>pizdec.xaml</code>:
  <p></p>
  
  <pre><code>protected override void OnNavigatedTo(NavigationEventArgs e)
     {
        base.OnNavigatedTo(e);
        string filename;
  
      if(NavigationContext.QueryString.TryGetValue("filename",out filename))
      {
          DisplayFile(filename);
      }
  </code></pre>
  
  <p><p>
  And <code>NavigationContext</code>, which no in 8.1
  <p>
  Please help</p>