title: Use UWP UI in WPF Application
body: <p>I have an application which runs in the background, but i wanted to add a Window with the UWP API.</p>
  
  <p>After adding the References to:</p>
  
  <pre><code>Windows.UI
  Windows.UI.Xaml
  </code></pre>
  
  <p>I tried to start the UWP application with:</p>
  
  <pre><code>Windows.UI.Xaml.Application.Start(p =&gt; new UWPApp(); );
  </code></pre>
  
  <p>In the UWPApp class i added the UWP template code:</p>
  
  <pre><code>using System;
  using System.Diagnostics;
  using Windows.ApplicationModel;
  using Windows.ApplicationModel.Activation;
  using Windows.UI.Xaml;
  using Windows.UI.Xaml.Controls;
  using Windows.UI.Xaml.Navigation;
  
  namespace ClipboardSync {
  
      public class UWPApp : Windows.UI.Xaml.Application {
  
          private bool _contentLoaded;
  
          public void InitializeComponent() {
              if (_contentLoaded)
                  return;
  
              _contentLoaded = true;
          }
  
          public UWPApp() {
              this.InitializeComponent();
              this.Suspending += OnSuspending;
          }
  
  
          protected override void OnLaunched(LaunchActivatedEventArgs e) {
              Frame rootFrame = Window.Current.Content as Frame;
  
              // Do not repeat app initialization when the Window already has content,
              // just ensure that the window is active
              if (rootFrame == null) {
                  // Create a Frame to act as the navigation context and navigate to the first page
                  rootFrame = new Frame();
  
                  rootFrame.NavigationFailed += OnNavigationFailed;
  
                  if (e.PreviousExecutionState == ApplicationExecutionState.Terminated) {
                      //TODO: Load state from previously suspended application
                  }
  
                  // Place the frame in the current Window
                  Window.Current.Content = rootFrame;
              }
  
              if (e.PrelaunchActivated == false) {
                  if (rootFrame.Content == null) {
                      // When the navigation stack isn't restored navigate to the first page,
                      // configuring the new page by passing required information as a navigation
                      // parameter
                      rootFrame.Navigate(typeof(MainPage), e.Arguments);
                  }
                  // Ensure the current window is active
                  Window.Current.Activate();
              }
          }
  
          /// &lt;summary&gt;
          /// Invoked when Navigation to a certain page fails
          /// &lt;/summary&gt;
          /// &lt;param name="sender"&gt;The Frame which failed navigation&lt;/param&gt;
          /// &lt;param name="e"&gt;Details about the navigation failure&lt;/param&gt;
          void OnNavigationFailed(object sender, NavigationFailedEventArgs e) {
              throw new Exception("Failed to load Page " + e.SourcePageType.FullName);
          }
  
          /// &lt;summary&gt;
          /// Invoked when application execution is being suspended.  Application state is saved
          /// without knowing whether the application will be terminated or resumed with the contents
          /// of memory still intact.
          /// &lt;/summary&gt;
          /// &lt;param name="sender"&gt;The source of the suspend request.&lt;/param&gt;
          /// &lt;param name="e"&gt;Details about the suspend request.&lt;/param&gt;
          private void OnSuspending(object sender, SuspendingEventArgs e) {
              var deferral = e.SuspendingOperation.GetDeferral();
              //TODO: Save application state and stop any background activity
              deferral.Complete();
          }
  
      }  
  
  }
  </code></pre>
  
  <p>but the new UWPApp Instance is never created and there is no error message.</p>
  
  <p>Is there some kind of restriction so that I can't start a UWP Application inside a WPF App?</p>