XPathNavigator.SetValue Sets the value of the current node.
using System; using System.Linq; using System.Xml; using System.Xml.Linq; using System.Collections; using System.Collections.Generic; using System.Xml.XPath; public class MainClass{ public static void Main(){ XmlDocument document = new XmlDocument(); document.Load("domainBooks.xml"); XPathNavigator navigator = document.CreateNavigator(); XmlNamespaceManager manager = new XmlNamespaceManager(navigator.NameTable); manager.AddNamespace("bk", "http://www.domain.com/books"); foreach (XPathNavigator nav in navigator.Select("//bk:price", manager)) { if (nav.Value == "11.99") { nav.SetValue("12.99"); } } Console.WriteLine(navigator.OuterXml); } }