title: How to find attribute value
body: <p>I need to find an inner text of an element inside an XmlDocument and return it's Xpath. for example, searching for "ThisText" inside :</p>
  
  <pre><code>&lt;xml&gt; 
  &lt;xml2 val="ThisText"&gt;&lt;/xml2&gt; 
  &lt;/xml&gt; 
  </code></pre>
  
  <p>should return the Xpath of xml2</p>
  
  <p>what's the most efficient way of doing this in c#?</p>