title: How to Notify IEnumerable
body: <p>When App.StaticLib.Search.SearchDetail is changed I call NotifyPropertyChanged on the collection.  </p>
  
  <pre><code>public enumSearchDetail SearchDetail
  {
      get { return searchDetail; }
      set
      {
          if (searchDetail == value) return;
          searchDetail = value;
          NotifyPropertyChanged("SearchDetail");
          NotifyPropertyChanged("SearchFieldsListCurrent");                    
      }
  }
  </code></pre>
  
  <p>But that does not cause UI elements bound to SearchFieldsListCurrent to get a fresh IEnumerable<br>
  It is a Collection but I can't figure out how to manually call a NotifyCollectionChanged</p>
  
  <pre><code>public IEnumerable&lt;FieldDef&gt; SearchFieldsListCurrent
  {
      get
      {
          if (App.StaticLib.Search.SearchDetail == enumSearchDetail.Basic) return SearchFieldsListBasic;
          if (App.StaticLib.Search.SearchDetail == enumSearchDetail.Advanced) return SearchFieldsListAdvanced;
          else return SearchFieldsList;
      }
      set { NotifyPropertyChanged("SearchFieldsListCurrent"); }
  }
  </code></pre>