c#怎么解析XML？

<?xml version="1.0" encoding="UTF-8" ?>
<items>
<rtnCode>000</rtnCode>
<result>AA</result>
<item>123</item>
<trans>
   <recode>
     <aaa>1111</aaa>
   </recode>
   <recode>
     <aaa>2222</aaa>
   </recode>
   <recode>
     <aaa>3333</aaa>
   </recode>
</trans>
</items>

有这样一段数据  <rtnCode>000</rtnCode>
我想解析数据当rtnCode=000 是执行 **操作  当=111时候在执行另外的操作。
主要想解析到rtnCode这个值就可以别的数据可以不用管，

要怎么解析呢？？  能写具体一点吗？谢谢~　　 --------------------编程问答-------------------- using System.xml.linq;
XDocument doc=XDocument.Load("xml文档");
if(doc.Element("rtnCode").Value=="000"）{}
手写板。。可能有错误 --------------------编程问答--------------------

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;



namespace WindowsApplicationTest

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }



        private void Form1_Load(object sender, EventArgs e)

        {

            String xml = @"<?xml version=""1.0"" encoding=""UTF-8"" ?>  

                          <Package>

                          <totalCount>45</totalCount>  

                          <MaxId>2878419</MaxId>  

                          <Message>

                          <DeliverMessage>

                          <Id>2878419</Id>  

                          <Userid>guodcy</Userid>  

                          <Srctermid>07168305533</Srctermid>  

                          <Desttermid>07168305533</Desttermid>  

                          <Content>湖电信测试</Content>  

                          <Receivetime>2010-06-27 21:26:54.0</Receivetime>  

                          </DeliverMessage>

                          </Message>

                          </Package>";

            System.Xml.XmlDocument doc = new System.Xml.XmlDocument();

            doc.LoadXml(xml);

            //Console.WriteLine("totalCount : " + doc.GetElementsByTagName("totalCount")[0].FirstChild.Value);

            textBox1.Text = "total:"+doc.GetElementsByTagName("totalCount")[0].FirstChild.Value+"\r\n";

            foreach (System.Xml.XmlNode node in doc.GetElementsByTagName("DeliverMessage"))

            {

                textBox1.Text = textBox1.Text + "id:" + node["Id"].FirstChild.Value + "\r\n";

                textBox1.Text = textBox1.Text + "Userid:" + node["Userid"].FirstChild.Value + "\r\n";

                textBox1.Text = textBox1.Text + "Srctermid:" + node["Srctermid"].FirstChild.Value + "\r\n";

                textBox1.Text = textBox1.Text + "Desttermid:" + node["Desttermid"].FirstChild.Value + "\r\n";

                textBox1.Text = textBox1.Text + "Content:" + node["Content"].FirstChild.Value + "\r\n";

                textBox1.Text = textBox1.Text + "Receivetime:" + node["Receivetime"].FirstChild.Value + "\r\n";

            }

        }

    }

}

--------------------编程问答--------------------

using System;

using System.Windows.Forms;

using System.Xml;



namespace xmlNode

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }



        private void button1_Click(object sender, EventArgs e)

        {

            XmlDocument xmldoc = new XmlDocument();

            xmldoc.Load("1.xml");

            XmlNode xn = xmldoc.SelectSingleNode("items/rtnCode");

            string s = xn.InnerText;

        }

    }

}

s就是你要的值  你再根据这个值判断执行啥子 --------------------编程问答-------------------- c#里有专门的函数把 --------------------编程问答-------------------- XmlDocument doc=new XmlDocument("");
doc.Load("");
XmlNode node=doc.SelectSingleNode("//rtnCode");
if(node!=null){} --------------------编程问答-------------------- XmlNode node=XmlDocment.SelectSingleNode("//itmes//rtncode");
可以参考
http://www.w3school.com.cn/xmldom/met_node_selectsinglenode.asp
--------------------编程问答-------------------- XmlDocument xmldoc = new XmlDocument();
            xmldoc.Load("xml路径");
            XmlNode node= xmldoc.SelectSingleNode("//rtnCode");
            if(node!=null)
            string s = node.InnerText;
--------------------编程问答--------------------

补充：.NET技术 ,  C#