xml新手，求教.net下取节点问题

Question

XmlDocument xmlDocument1 = this.CreateDoc("/1.xml");
XmlNode xmlNode3 = xmlDocument1.SelectSingleNode("urlrewritingnet/rewrites");
此时xmlNode3是空的，不知什么原因找不到节点1.xml内容格式如下：
<?xml version="1.0" encoding="utf-8" ?>
<urlrewritingnet
    rewriteOnlyVirtualUrls="true" 
    contextItemsPrefix="QueryString"
    defaultPage = "default.aspx"
    defaultProvider="RegEx"
    xmlns="http://www.urlrewriting.net/schemas/config/2006/07" >
<rewrites>
<add name="home"  virtualUrl="^~/default.aspx"
          rewriteUrlParameter="ExcludeFromClientQueryString"
          destinationUrl="~/default.aspx"
          ignoreCase="true" />
        <add name="aboutus"  virtualUrl="^~/aboutus.aspx"
          rewriteUrlParameter="ExcludeFromClientQueryString"
          destinationUrl="~/aboutus.aspx"
          ignoreCase="true" />
        ........
        ........
  </rewrites>
</urlrewritingnet>请xml高手解惑

Answer 1

http://topic.csdn.net/u/20080804/23/050b4055-4d9b-4275-a146-85261af627bc.html

Answer 2

XmlDocument xmlDocument1 = this.CreateDoc("/1.xml"); 
XmlNamespaceManager nm = new XmlNamespaceManager(doc.NameTable);
nm.AddNamespace("uu", "http://www.urlrewriting.net/schemas/config/2006/07");
XmlNode node = xmlDocument1.SelectSingleNode("/uu:urlrewritingnet/uu:rewrites", nm);

Answer 3

ls,报错，说上下文不存在名称doc

Answer 4

可以了，改一下，呵，tks,结贴