title: DataTemplate inside DataTemplate - ListBox inside ListBox
body: <p>I want to use dataTemplale inside dataTemplate.
  I want to display data in list box like that:</p>
  
  <pre><code>&lt;RoomName&gt;
      &lt;Kid Name&gt;
      &lt;Kid Name&gt;
  &lt;RoomName&gt;
      &lt;Kid Name&gt;
  &lt;RoomName&gt;
      &lt;Kid Name&gt;
      &lt;Kid Name&gt;
      &lt;Kid Name&gt;
  </code></pre>
  
  <p>This is what I got. It's not working.</p>
  
  <pre><code>class Room
  {
    ObservableCollection&lt;kid&gt; Kids = new Ob...
  }
  
  class School
  {
    ObservableCollection&lt;Room&gt; Rooms = new Ob...
  }
  
  class kid
  {
    Name;
    Size;
    (...)
  }
  </code></pre>
  
  <p>This is my binding from code:</p>
  
  <pre><code>School BigSchool = new School();
  MainListBox.DataContext = BigSchool;
  </code></pre>
  
  <p>This is my Window XAML:</p>
  
  
  
  <pre class="lang-xml prettyprint-override"><code>&lt;Window
          xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
          xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
          xmlns:local="clr-namespace:Rapideo_Client" mc:Ignorable="d"
          x:Class="Rapideo_Client.MainWindow"
          Title="Client" SnapsToDevicePixels="True" Height="400" Width="625"&gt;
      &lt;Window.Resources&gt;
          &lt;DataTemplate x:Key="kidTemplate" DataType="Kid"&gt;
              &lt;StackPanel Orientation="Vertical"&gt;
                  &lt;TextBlock Text="{Binding Path=Name}" FontWeight="Bold"&gt;&lt;/TextBlock&gt;
                  &lt;Label Content="{Binding Path=Size}"/&gt;
              &lt;/StackPanel&gt;
          &lt;/DataTemplate&gt;
          &lt;DataTemplate x:Key="roomTemplate" DataType="Room"&gt;
              &lt;StackPanel Orientation="Vertical"&gt;
                  &lt;Label Content="{Binding Path=Kids.Count}"/&gt;
                  &lt;ListBox ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Disabled" ItemsSource="{Binding Path=Kids}" ItemTemplate="{DynamicResource kidTemplate}" /&gt;
              &lt;/StackPanel&gt;
          &lt;/DataTemplate&gt;
      &lt;/Window.Resources&gt;
  
      &lt;ListBox ScrollViewer.HorizontalScrollBarVisibility="Disabled" ScrollViewer.VerticalScrollBarVisibility="Visible" x:Name="MainListBox" Grid.Column="1" ItemsSource="{Binding Rooms}" ItemTemplate="{DynamicResource roomTemplate}" /&gt;
  
  &lt;/Window&gt;
  </code></pre>