title: Delete all items from a list
body: <p>I want to delete all the elements from my list:</p>
  
  <pre><code>foreach (Session session in m_sessions)
  {
      m_sessions.Remove(session);
  }
  </code></pre>
  
  <p>In the last element I get an exception: UnknownOperation.</p>
  
  <p>Anyone know why?</p>
  
  <p>how should I delete all the elements? It is ok to write something like this:</p>
  
  <pre><code>m_sessions = new List&lt;Session&gt;();
  </code></pre>