title: Select first item in Silverlight combobox using MVVM pattern
body: <p>This is my first foray in MVVM and I've now encountered the following issue:</p>
  
  <p>I've got my ViewModel:</p>
  
  <pre><code>  public List&lt;WorkCellGroupInfo&gt; WorkCellGroupInfoCollection
      {
          get
          {
              return _workCellGroupInfoCollection;
          }
          set
          {
              _workCellGroupInfoCollection = value;
              NotifyPropertyChanged( "WorkCellGroupInfoCollection" );
  
              SelectedWorkCellGroup = _workCellGroupInfoCollection.FirstOrDefault();
          }
      }
  
      public WorkCellGroupInfo SelectedWorkCellGroup
      {
          get
          {
              return _selectedWorkCellGroup;
          }
          set
          {
              _selectedWorkCellGroup = value;
              NotifyPropertyChanged( "SelectedWorkCellGroup" );
          }
      }
  </code></pre>
  
  <p>and my XAML:</p>
  
  <pre><code>&lt;ComboBox x:Name="WorkCellGroup" 
  ItemsSource="{Binding WorkCellGroupInfoCollection}" 
  SelectedItem="{Binding SelectedWorkCellGroup, Mode=TwoWay}" 
  DisplayMemberPath="Name"&gt;
  </code></pre>
  
  <p>On the first load the combobox gets populated with the data but I can't get the first item selected. What am I doing wrong?</p>
  
  <p>The WorkCellGroupInfo is derived from the FilterBase class:</p>
  
  <pre><code>public abstract class FilterBase
  {
      public string Id
      {
          get;
          set;
      }
  
      public string Name
      {
          get;
          set;
      }
  }
  </code></pre>