title: DirectorySearcher contains filter on two properties
body: <p>I need to search users in active directory and apply 'contains' filter on two concatenated properties. So it should be something like:  </p>
  
  <pre><code>(&amp;(objectClass=user)(property1 + " " + property2=*keyword*))  
  </code></pre>
  
  <p>Is it possible to achieve this with DirectorySearcher?</p>