XmlNode root=xmlDoc.DocumentElement.SelectSingleNode("voucher");
这个是查找到voucher节点.
如果有多个voucher节点,循环的时候怎么能查找到下一个voucher节点啊??

XmlNodeList nodes=doc.SelectSingleNode("voucher").ChildNodes;
foreach (XmlNode xn in nodes)
{
XmlElement xe = (XmlElement)xn;
if (xe.GetAttribute("name") == "111")
{
XmlNodeList nl = xe.ChildNodes;
foreach (XmlNode xnd in nl)
{
XmlElement xx=(XmlElement)xnd;
if (xx.GetAttribute("name") == "222")
{
xx.SetAttribute("name", "333");
break;
}
}
break;
}