<?xml version="1.0" encoding="utf-8" ?>
<config>
  <serv_ip>192.168.0.105</serv_ip>
  <database>test</database>
  <userid>sa</userid>
  <password>123456</password>
</config>

            XmlDocument xmlDoc = new XmlDocument();
            xmlDoc.Load("config.xml");
            XmlNode root = xmlDoc.SelectSingleNode("config");//指向根节点
            XmlNode xn = root.SelectSingleNode("serv_ip");//指向根节点下的serv_ip节点
            string ip = xn.InnerText;//读出里面的值 注意读取的是string 需要类型转换的话自己做
            XmlNode database = root.SelectSingleNode("database");
            string data = database.InnerText;
            XmlNode userid = root.SelectSingleNode("userid");
            string user = userid.InnerText;
            XmlNode password = root.SelectSingleNode("password");
            string pwd = password.InnerText;