//先搞个struct声明

        private struct datastruct

        {

            public string x;

            public string y;

            public string z;

        }

private void sort()
{
　　 int i = intIndex + ;//索引定位

     XmlNodeList xnl = xmlRoot.ChildNodes;

     datastruct dt0 = new datastruct();

     datastruct dt1 = new datastruct();

     foreach (XmlNode xn in xnl)

     {

          XmlElement xe = (XmlElement)xn;
　　　　　　//替换，原数据存入struct

          if (xe.GetAttribute("id") == TextBox1.Text)

          {

               XmlNodeList xnf1 = xe.ChildNodes;

               dt0.x = xnf1[].InnerText;

               dt0.y = xnf1[].InnerText;

               dt0.z = xnf1[].InnerText;

               xnf1[].InnerText = TextBox2.Text;

               xnf1[].InnerText = TextBox3.Text;

               xnf1[].InnerText = TextBox4.Text;

           }
　　　　}
　　　　//增加尾节点       
　　　　XmlElement xe1 = xmlDoc.CreateElement("Item");

       xe1.SetAttribute("id", (listview.Items.Count+).ToString());

       XmlElement xesub1 = xmlDoc.CreateElement("X");

       xesub1.InnerText = dt1.x;

       xe1.AppendChild(xesub1);

       XmlElement xesub2 = xmlDoc.CreateElement("Y");

       xesub2.InnerText = dt1.y;

       xe1.AppendChild(xesub2);

       XmlElement xesub3 = xmlDoc.CreateElement("Z");

       xesub3.InnerText = dt1.z;

       xe1.AppendChild(xesub3);

       xmlRoot.AppendChild(xe1);
}