title: Sorting the items in a combobox
body: <p>I have a combobox binded to an observable collection. I am using CollectionViewSource to sort the items in the combobox alphabetically.</p>
  
  <pre><code>&lt;CollectionViewSource x:Key="EmployeeViewSource" Source="{Binding LstEmployeeDetails}"&gt;
          &lt;CollectionViewSource.SortDescriptions&gt;
              &lt;scm:SortDescription PropertyName="EmployeeName" Direction="Ascending"/&gt;
          &lt;/CollectionViewSource.SortDescriptions&gt;
      &lt;/CollectionViewSource&gt;
  </code></pre>
  
  <p>And then I bind it to my combobox like this:</p>
  
  <pre><code>&lt;ComboBox x:Name="CmbboxEmployeeName" ItemsSource="{Binding Source={StaticResource EmployeeViewSource}}"/&gt;
  </code></pre>
  
  <p>The problem is I have two items in the collection that I don't want to sort. They are</p>
  
  <p>--Select-- and "Add New". I want that these two items should always be displayed on top and then the rest of the items should be sorted alphabetically. Also, when I add a new item to the list, it should get sorted automatically. </p>