title: Get child node value from xml using xpath
body: <pre><code>    &lt;Demo_Test&gt;
        &lt;Step ID="1"&gt;
          &lt;ACTION&gt;Point&lt;/ACTION&gt;
          &lt;CLASS_ID&gt;dfsfsdf&lt;/CLASS_ID&gt;
        &lt;/Step&gt;
      &lt;Step ID="2"&gt;
          &lt;ACTION&gt;Point&lt;/ACTION&gt;
          &lt;CLASS_ID&gt;Avkddd&lt;/CLASS_ID&gt;
        &lt;/Step&gt;
      &lt;Step ID="3"&gt;
          &lt;ACTION&gt;Point&lt;/ACTION&gt;
          &lt;CLASS_ID&gt;afsasfa&lt;/CLASS_ID&gt;
        &lt;/Step&gt;
     &lt;Step ID="4"&gt;
          &lt;ACTION&gt;SubAction&lt;/ACTION&gt;
          &lt;CLASS_ID&gt;afsasfa&lt;/CLASS_ID&gt;
        &lt;/Step&gt;
      &lt;/Demo_Test&gt;
  </code></pre>
  
  <p>I want to modify value of "CLASS_ID" having "Action" node value is "Point"
  For that i have written below code but doesn't work</p>
  
  <pre><code> string l_xPath = "//Step/ACTION["Point"]";
   XmlNodeList l_nodeList = l_doc.SelectNodes(l_xPath);
  </code></pre>