title: Issue binding grouped data to cvs for semantic zoom
body: <p>I'm having some trouble getting my semantic zoom bind correctly to my CollectionViewSource. I'm pretty new to MVVM, so I'm not sure i have stuff setup correctly.</p>
  
  <p>View Model</p>
  
  <pre><code>    private async void GetData()
      {
          // Simulate pulling data from api
          string response;
          StorageFile file = await StorageFile.GetFileFromApplicationUriAsync(new Uri(@"ms-appx:///DesignData/GetLive.json"));
          using (StreamReader sRead = new StreamReader(await file.OpenStreamForReadAsync()))
              response = await sRead.ReadToEndAsync();
  
          // Deserialize data to class
          LiveStreamModel liveGames = JsonConvert.DeserializeObject&lt;LiveStreamModel&gt;(response);
          Schedules = liveGames.schedule;
  
          // Group data by event
          var groupData = liveGames.schedule.GroupBy(a =&gt; a.@event);
  
          // Set cvs source to grouped data
          ScheduleSource = new CollectionViewSource() { IsSourceGrouped = true, Source = groupData };
      }
  
      private CollectionViewSource scheduleSource;
      public CollectionViewSource ScheduleSource
      {
          get
          {
              return scheduleSource;
          }
          set
          {
              scheduleSource = value;
              RaisePropertyChanged("ScheduleSource");
          }
      }
  </code></pre>
  
  <p>View</p>
  
  <pre><code>Page.Resources&gt;
      &lt;DataTemplate x:Key="ZoomedInTemplate"&gt;
          &lt;StackPanel Orientation="Horizontal" MinWidth="200" Margin="12,6,0,6"&gt;
              &lt;!--&lt;Image Source="{Binding ImagePath}" Height="80" Width="80"/&gt;--&gt;
              &lt;StackPanel Margin="20,0,0,0"&gt;
                  &lt;TextBlock Text="{Binding homeTeam}" Style="{StaticResource BaseTextBlockStyle}"/&gt;
                  &lt;TextBlock Text="{Binding awayTeam}" TextWrapping="Wrap" HorizontalAlignment="Left" Width="300" 
                             Style="{StaticResource BodyTextBlockStyle}"/&gt;
              &lt;/StackPanel&gt;
          &lt;/StackPanel&gt;
      &lt;/DataTemplate&gt;
  
      &lt;DataTemplate x:Key="ZoomedInGroupHeaderTemplate"&gt;
          &lt;TextBlock Text="{Binding event}" Foreground="{ThemeResource ApplicationForegroundThemeBrush}" 
                     Style="{StaticResource SubtitleTextBlockStyle}"/&gt;
      &lt;/DataTemplate&gt;
  
      &lt;DataTemplate x:Key="ZoomedOutTemplate"&gt;
          &lt;TextBlock Text="{Binding event}" Style="{StaticResource SubtitleTextBlockStyle}"/&gt;
      &lt;/DataTemplate&gt;
  &lt;/Page.Resources&gt;
  
  &lt;Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}"&gt;
      &lt;SemanticZoom x:Name="GetLiveZoom"  &gt;
          &lt;SemanticZoom.ZoomedInView&gt;
              &lt;GridView x:Name="GetLiveGrid" ItemsSource="{Binding ScheduleSource.View}" ItemTemplate="{StaticResource ZoomedInTemplate}" SelectionMode="Single"
                      ScrollViewer.IsHorizontalScrollChainingEnabled="False"&gt;
                  &lt;GridView.GroupStyle&gt;
                      &lt;GroupStyle HeaderTemplate="{StaticResource ZoomedInGroupHeaderTemplate}" /&gt;
                  &lt;/GridView.GroupStyle&gt;
              &lt;/GridView&gt; 
          &lt;/SemanticZoom.ZoomedInView&gt;
          &lt;SemanticZoom.ZoomedOutView&gt;
              &lt;GridView x:Name="GetLiveList" ItemsSource="{Binding ScheduleSource.View.CollectionGroups}" ItemTemplate="{StaticResource ZoomedOutTemplate}" SelectionMode="None"
                      ScrollViewer.IsVerticalScrollChainingEnabled="False"/&gt;
          &lt;/SemanticZoom.ZoomedOutView&gt;
      &lt;/SemanticZoom&gt;
  &lt;/Grid&gt;
  </code></pre>
  
  <p>When debugging, my data is getting grouped properly by <code>@event</code>, but setting the source of the cvs to the grouped data and binding that to the semantic zoom control results in nothing showing up. </p>