title: ObservableCollection and CollectionChanged Event
body: <p>Why does the collectionchanged event not fire in the following code, yet I can see the new instance of InventoryBTO I add to the ObservableCollection? </p>
  
  <pre><code> private ObservableCollection&lt;InventoryBTO&gt; _inventoryRecords;
      public ObservableCollection&lt;InventoryBTO&gt; InventoryRecords
      {
          get { return _inventoryRecords; }
          set { _inventoryRecords = value; }
      }
  
      private InventoryBTO _selectedRecord;
      public InventoryBTO SelectedRecord
      {
          get { return _selectedRecord; }
          set 
          {
              if (_selectedRecord != value)
              {
                  _selectedRecord = value;
                  OnPropertyChanged(new PropertyChangedEventArgs("SelectedRecord"));
              }
          }
      }
  
      public InventoryViewModel()
      {
          if (_inventoryRecords == null)
          {
              InventoryRecords = new ObservableCollection&lt;InventoryBTO&gt;();
              this.InventoryRecords.CollectionChanged += new NotifyCollectionChangedEventHandler(InventoryRecords_CollectionChanged);
          }
  
          _inventoryRecords = InventoryListBTO.GetAllInventoryRecords();
      }
  
      void InventoryRecords_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
      {
  
      } 
  </code></pre>