title: Raise CollectionChanged in ObservableCollection when an item's property is modified
body: <p>I am trying to bind the results of a LINQ query of an <code>ObservableCollection</code> to my UI and I seem to have it halfway working. If I add a new item to the <code>ObservableCollection</code>, I can raise CollectionChanged and call PropertyChanged on the property and it will update. Unfortunately, modifying a property of an item doesn't cause CollectionChanged to fire and I can't figure out how to make it fire. I have tried methods that others have posted such as <a href="https://stackoverflow.com/a/5256827/1667020">TrulyObservableColection</a> with no luck. Is there any way to force CollectionChanged to fire? Or is there another route I can take in this situation. I would rather not have to abandon LINQ. Any advice would be appreciated.</p>
  
  <pre><code>private ObservableCollection&lt;Worker&gt; _workers = new ObservableCollection&lt;Worker&gt;();
  public ObservableCollection&lt;Worker&gt; Workers
  {
      get { return _workers; }
  }
  </code></pre>
  
  <hr>
  
  <pre><code>public IEnumerable&lt;Worker&gt; WorkersEmployed
  {
      get { return GameContainer.Game.Workers.Where(w =&gt; w.EmployerID == this.ID); }
  }
  
  GameContainer.Game.Workers.CollectionChanged += Workers_CollectionChanged;
  
  private void Workers_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
  {
      RaisePropertyChanged(() =&gt; WorkersEmployed);
  }
  </code></pre>
  
  <p>This works assuming a new entry is added to the collection. How can I achieve the same result when an item is simply modified (such as Workers' EmployerID in this case)?</p>