title: Create UserControl ComboBox with Button
body: <p>I'm trying to create an UserControl that have a ComboBox with a list of items and then I want to add a button to perform some action.</p>
  
  <p>I have this code:</p>
  
  <p>ComboBoxWithButton XAML:</p>
  
  <pre><code>&lt;ComboBox x:Name="ComboBoxBtn" VerticalAlignment="Top" HorizontalAlignment="Left" Margin="0,0,0,-1" Width="100" ItemsSource="{Binding Source}"&gt;
          &lt;ComboBox.ItemTemplate&gt;
              &lt;DataTemplate&gt;
                  &lt;Grid&gt;
                      &lt;Grid.ColumnDefinitions&gt;
                          &lt;ColumnDefinition Width="Auto" /&gt;
                          &lt;ColumnDefinition Width="Auto" /&gt;
                      &lt;/Grid.ColumnDefinitions&gt;
                      &lt;Label Content="{Binding }" Width="100" /&gt;
                      &lt;Button Grid.Column="1"&gt;Something&lt;/Button&gt;
                  &lt;/Grid&gt;
              &lt;/DataTemplate&gt;
          &lt;/ComboBox.ItemTemplate&gt;
      &lt;/ComboBox&gt;
  </code></pre>
  
  <p>ComboBoxWithButton Code:</p>
  
  <pre><code>public ComboBoxWithButton()
          {
              InitializeComponent();
          }
  
  
          public static readonly DependencyProperty SourceProprety =
              DependencyProperty.Register("Source", typeof(ObservableCollection&lt;object&gt;), typeof(ComboBoxWithButton), new PropertyMetadata(null));
  
          public ObservableCollection&lt;object&gt; Source
          {
              get { return (ObservableCollection&lt;object&gt;)GetValue(ValueProprety); }
              set { SetValue(ValueProprety, value); }
          }
  </code></pre>
  
  <p>Then on my Window I call:</p>
  
  <pre><code>&lt;controls:ComboBoxWithButton Source="{Binding SomeCollection}"/&gt;
  </code></pre>
  
  <p>But the combobox is empty</p>