title: EF5 SaveChanges with MVVM
body: <p>I'm writing a first MVVM application in WPF using EF5 with a "Database First" approach.
  My model in the MVVM is what EF5 has generated for me (I did need to customize the T4 template to include INotifyPropertyChanged).</p>
  
  <p>Everything seems to work fine, changing the text in a textbox raised a propertychanged in my model.
  I am now trying to save these changes to the database. I get no error, but the changes are not submitted. </p>
  
  <p>I'm afraid that, performing a context.savechanges() in my viewmodel is not enough?</p>
  
  <pre><code>private void UpdatePerson()
      {
          using (CvContext ctx = new CvContext())
          {
              ctx.SaveChanges();
          }
      }
  </code></pre>
  
  <p>in my XAML I have:</p>
  
  <pre><code>&lt;UserControl.DataContext&gt;
      &lt;myViewModels:PersonDetailViewModel/&gt;
  &lt;/UserControl.DataContext&gt;
  &lt;TextBox Grid.Row="1" Grid.Column="1" x:Name="txtLastName" Text="{Binding Path=Lastname}"&gt;&lt;/TextBox&gt;
  </code></pre>
  
  <p>Do I need to define insert/update/delete in the edmx designer or is this not really necessary?</p>
  
  <p>Thanks in advance for your help!
  Best regards,
  YK</p>