Change each value of same xml node with current date time

Question

My xml is:

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <sitemap>
    <loc>http://localhost:2511/SF/sitemap_1.xml</loc>
    <lastmod>2013-11-11T04:17:57+00:00</lastmod>
  </sitemap>
  <sitemap>
    <loc>http://localhost:2511/SF/sitemap_2.xml</loc>
    <lastmod>2013-11-11T04:17:57+00:00</lastmod>
  </sitemap>
</urlset>

And I try to change each <lastmod> value like this :

XmlDocument doc = new XmlDocument();
doc.Load(HttpRuntime.AppDomainAppPath + "sitemap_index.xml"); //Doc is loaded successfully

//XmlNodeList nodeList = doc.SelectNodes("/urlset/sitemap/lastmod");//I also try this one
 XmlNodeList nodeList = doc.DocumentElement.SelectNodes("/urlset/sitemap/lastmod");
 foreach (XmlNode xmlNode in nodeList)
  {
     xmlNode.InnerText = DateTime.Now.ToString();
  }

But I always get nodeList count 0. What is my mistake.Thanks for help.

Answer 1

Replace this line

XmlNodeList nodeList = doc.DocumentElement.SelectNodes("/urlset/sitemap/lastmod");

with

XmlNodeList nodeList = doc.GetElementsByTagName("lastmod");