title: WP8.1 Detecting screen capture occurred
body: <p>I know how to prevent a user from performing a screen capture on WP8.1 Now I want to allow screen capture and keep track of who does this.</p>
  
  <p>Here is what I've tried so far.</p>
  
  <pre><code>public async Task StartScreenshotDetection()
  {
      try
      {
          var picturesLibrary = Windows.Storage.KnownFolders.PicturesLibrary;
          string picsPath = picturesLibrary.Path;
  
          StorageFolder screenshotsLibrary = await picturesLibrary.GetFolderAsync("Screenshots");
          String[] types = { ".png" };
          var options = new Windows.Storage.Search.QueryOptions(Windows.Storage.Search.CommonFileQuery.DefaultQuery, types);
  
          if (screenshotsLibrary.AreQueryOptionsSupported(options))
          {
              var query = screenshotsLibrary.CreateFileQueryWithOptions(options);
  
              query.ContentsChanged += QueryContentsChanged; //subscription
  
              var throwawayResult = await query.GetFilesAsync(); // needed to get events to fire
  
              int a = 1;
          }
      }
      catch (Exception ex)
      {
          int b = 1;
      }
  }
  
  void QueryContentsChanged(Windows.Storage.Search.IStorageQueryResultBase sender, object args)
  {
      var a = 1;
      // handle changes
  }
  </code></pre>
  
  <p>The issue I'm having is creating a new QueryOptions throws Unimplemented exception. The docs seem to imply WP8.1 is supported. </p>
  
  <p>Is there another way to detect screen capture? Your help is appreciated.</p>