title: combine multiple tracesource filters in app.config
body: <p>I want to configure a FileTraceListeners in my application, that ignores 'verbose' level messages but logs 'information' level and above as well as 'start' and 'stop' events.</p>
  
  <p>Everything is configured within the app.config file.
  However I cannot find the correct syntax for combining these different trace levels. 
  <a href="http://msdn.microsoft.com/en-us/library/ms229326.aspx" rel="nofollow">The Syntax for filters is explained here</a>. </p>
  
  <p>Using a single filter for 'information' will correctly filter out everything that is not 'information', 'warning' 'error' or 'critical'. However I also want to include 'start' and 'stop' events.</p>
  
  <p>I tried using 2 filters :</p>
  
  <pre class="lang-xml prettyprint-override"><code>&lt;filter type="System.Diagnostics.EventTypeFilter" initializeData="Information"/&gt;
  &lt;filter type="System.Diagnostics.EventTypeFilter" initializeData="ActivityTracing"/&gt;
  </code></pre>
  
  <p>I tried combining the initializeDate </p>
  
  <p>with commas:
  <code>initializeData="Information,ActivityTracing"</code> </p>
  
  <p>or semicolons  <code>initializeData="Information;ActivityTracing"</code></p>
  
  <p>everything will just cause a syntax error.</p>
  
  <p>How do I combine these two filters inside app.config?</p>
  
  <p>(I am using the native .net 3.5 logging libraries and do not wish to change to log4net or another framework at this point.)</p>