title: set SelectedIndex of Combobox in WPF to 0
body: <p>I am binding a Collection at run time to a Combobox and I would like to set the Index after to 0. I could not find a straight answer to what I want.</p>
  
  <pre><code>_stationNames = new ObservableCollection&lt;string&gt;(_floorUnits.Unit.Select(f =&gt; f.Name));
  _stationNames.Insert(0, "All");
  stationsComboBox.ItemsSource = _stationNames;
  stationsComboBox.SelectedIndex = 0;//Doesn;t work
  </code></pre>
  
  <p>Xaml</p>
  
  <pre><code>&lt;ComboBox x:Name="stationsComboBox" Grid.Row="1" Grid.Column="1" Text="{Binding Name}"
                    SelectionChanged="StationComboBoxSelectionChanged" VerticalAlignment="Center" Margin="3"
                     SelectedIndex="0"/&gt;
  </code></pre>