XPathDocument document = new XPathDocument("books.xml");
XPathNavigator navigator = document.CreateNavigator();

XPathNodeIterator nodes = navigator.Select("/bookstore/book");
nodes.MoveNext();
XPathNavigator nodesNavigator = nodes.Current;

XPathNodeIterator nodesText = nodesNavigator.SelectDescendants(XPathNodeType.Text, false);

while (nodesText.MoveNext())
    Console.WriteLine(nodesText.Current.Value);

XPathDocument document = new XPathDocument("books.xml");
XPathNavigator navigator = document.CreateNavigator();

XPathExpression query = navigator.Compile("/bookstore/book");
XPathNodeIterator nodes = navigator.Select(query);
XPathNavigator nodesNavigator = nodes.Current;

XPathNodeIterator nodesText = nodesNavigator.SelectDescendants(XPathNodeType.Text, false);

while (nodesText.MoveNext())
{
    Console.WriteLine(nodesText.Current.Value);
}

XPathDocument document = new XPathDocument("contosoBooks.xml");
XPathNavigator navigator = document.CreateNavigator();
XmlNamespaceManager manager = new XmlNamespaceManager(navigator.NameTable);
manager.AddNamespace("bk", "http://www.contoso.com/books");

XPathNodeIterator nodes = navigator.Select("/bk:bookstore/bk:book/bk:price", manager);
// Move to the first node bk:price node
if(nodes.MoveNext())
{
    // now nodes.Current points to the first selected node
    XPathNavigator nodesNavigator = nodes.Current;

    //select all the descendants of the current price node
    XPathNodeIterator nodesText = 
       nodesNavigator.SelectDescendants(XPathNodeType.Text, false);

    while(nodesText.MoveNext())
    {
       Console.WriteLine(nodesText.Current.Value);
    }
}

//引入命名空间
using System;
using System.Collections.Generic;
using System.Data;
using System.Text;
using System.Xml;
using System.Xml.XPath;

public class MainClass {
    public static void Main() {
        XPathDocument doc = new XPathDocument("books.xml");
        XPathNavigator nav = ((IXPathNavigable)doc).CreateNavigator();
        XPathNodeIterator iter = nav.Select("/bookstore/book[@genre='novel']");
        while (iter.MoveNext()) {
            XPathNodeIterator newIter = iter.Current.SelectDescendants(XPathNodeType.Element, false);
            while (newIter.MoveNext())
                Console.WriteLine(newIter.Current.Name + ": " + newIter.Current.Value);
        }
    }
}