title: How to get object from binding source
body: <p>In WPF, I have a listbox binding to a Dataset which looks like:</p>
  
  <pre><code>&lt;ListBox x:Name="lb_Configuration" SelectionMode="Extended" Height="100" ItemsSource="{Binding Products}" SelectedItem="{Binding SelectedProduct}"&gt;
  </code></pre>
  
  <p>The SelectedItem has many objects like: <em>id</em>, <em>name</em>, <em>value</em>...</p>
  
  <p>How could I get this value in the back end code? my thought is：</p>
  
  <pre><code>int myid;
  myid = lb_Configuration.SelectedItem.&lt;what method?&gt;
  </code></pre>
  
  <p>Or someother way to achieve my purpose？Thanks.</p>