title: data binding TextBox TextChanged is not working
body: <p>I'm have two TextBoxes (<strong>XAML</strong>)</p>
  
  <pre><code>&lt;s:SurfaceTextBox Name="CodePostal" TextChanged="CodePostalChanged" /&gt;
  &lt;s:SurfaceTextBox Name="Commune" Text="{Binding Path=CommuneGeographique}" /&gt;
  </code></pre>
  
  <p>And in the (<strong>.cs file</strong>)</p>
  
  <pre><code>private MyModelContainer db;
  private ObservableCollection&lt;Commune&gt; _CommunesList = new ObservableCollection&lt;Commune&gt;();
  private ObservableCollection&lt;Commune&gt; CommunesList 
  { 
      get { return _CommunesList; }
      set { _CommunesList = value; }
  }
  </code></pre>
  
  <p>In the <strong>constructor</strong>, I have this :</p>
  
  <pre><code>InitializeComponent();
  getCommunes("Test");
  </code></pre>
  
  <p>And <strong>getCommunes(string search)</strong>, is a Linq query</p>
  
  <pre><code>db = new MyModelContainer();
  
  CommunesList.Clear();
  Commune.DataContext = _CommunesList;
  
  var myCommunes = from d in db.Communes
                   where d.CommunePostale.Equals(search)
                   select d;
  
  foreach (Commune c in myCommunes)
  {
      CommunesList.Add(c);
  }
  
  Commune.DataContext = CommunesList;
  </code></pre>
  
  <p>At this point everything works fine and the Commune TextBox displays what I want.</p>
  
  <p>My problem is that when I try to call the getCommunes() method on a TextChanged</p>
  
  <pre><code>private void CodePostalChanged(object sender, TextChangedEventArgs textChangedEventArgs)
  {
      getCommunes("Toto");
  }
  </code></pre>
  
  <p>Nothing happens and the TextBox is cleared.</p>
  
  <p>(It should display something else, but its empty even if the CommuneList has an element)</p>