title: Entity Framework - Code First, DbSet.Local Not Updating in UI
body: <p>I have a Code First, CTP5 data context.  I have a WPF app with a DataGrid.  I set its DataContext like:</p>
  
  <pre><code>dataGrid.DataContext = _context.Customers.Local;
  </code></pre>
  
  <p>then I add a few entities using</p>
  
  <pre><code>_context.Customers.Add(customer1); and so on
  _context.SaveChanges();
  </code></pre>
  
  <p>Then, I give these customers (a list of the customers) to another class to do some work on them.</p>
  
  <pre><code>customerUpdater.Update(customers);
  </code></pre>
  
  <p>That takes a long time and it updates properties of each customer while it's working. e.g.</p>
  
  <pre><code>foreach(var customer in customers) { customer.Name = "updated name"; }
  </code></pre>
  
  <p>I'm not seeing those updates in my WPF UI though!  All I see are the original list of unaltered customers.  Customers.Local is an ObservableCollection though, so I don't understand why I'm not seeing the updates in the UI.</p>
  
  <p>I don't want to call SaveChanges() every time a property update occurs, it would be nearly constantly.  Can someone tell me why this won't update?</p>