title: check if a textbox value already exists in a listbox
body: <p>I have a ListBox bound to a observableCollection of "widgets".  Each widget in the collection only has a name field at the moment but that will change.</p>
  
  <p>On the window I have a text box where a user can enter another name for addition to the observableCollection.</p>
  
  <p>Each entry has to be unique.  </p>
  
  <p>At the moment I use this</p>
  
  <pre><code>  Dim query As IEnumerable(Of clsWidget)
    query = WidgetSource.Where(Function(widget) widget.name = txtNewName.Text)
  
    If query.Count &gt; 0 Then
      Debug.Print("Tried to add a widget that already in the collection")
    End If
  </code></pre>
  
  <p>Is there a more efficient way of doing this?</p>