<?xml version="1.0" encoding="utf-8"?>
<nodes>
  <node>
    <nodecode>1</nodecode>
  </node>
  <node>
    <nodecode>2</nodecode>
  </node>
</nodes>

------解决方案--------------------
<asp:XmlDataSource runat="server" ID="xmlDataSource1" DataFile="test.xml"></asp:XmlDataSource>
1.设置好DataFile
2.后台更新xml操作
test.xml
XML code
<?xml version="1.0" encoding="utf-8"?>
<nodes>
  <node>
    <nodecode>1</nodecode>
  </node>
  <node>
    <nodecode>2</nodecode>
  </node>
</nodes>

------解决方案--------------------

private void btnSave_Click(object sender, EventArgs e)
       {
           string SaveFile = @"c:\\test.xml";
           sr = new StreamWriter(SaveFile, false, System.Text.Encoding.UTF8);
           sr.WriteLine("<?xml version=\"1.0\" encoding=\"utf-8\" ?>");
           sr.WriteLine("<root>");
           GetXml(treeView1.Nodes);
           sr.WriteLine("</root>");
           sr.Close();
       }
       StreamWriter sr;      
       /// 递归Treeview写入XML文件
       private void GetXml(TreeNodeCollection tnc)
       {
           foreach (TreeNode node in tnc)
           {
               if (node.Parent != null)
               {
                   sr.WriteLine("<A>");

                   sr.WriteLine("<Name>" + node.Text + "</Name>");
                 
                   GetXml(node.Nodes);

                   sr.WriteLine("</A>");
               }
               else
                   GetTvXml(node.Nodes);
           }
       }

http://www.cnblogs.com/wf5360308/articles/1227700.html


------解决方案--------------------
XmlDocument xmlDoc = new XmlDocument();
  xmlDoc = (XmlDocument)this.xmlDataSource1.GetXmlDocument();
  XmlNode node = xmlDoc.SelectSingleNode("//nodes/node/nodecode[text()='2']");//test为2的nodecode节点
  if(node!=null)
  {
   node.InnerText = "222";//修改节点值
  }
  this.xmlDataSource1.Save();//保存test.xml
====
你修改一下xmlDataSource1的XmlDocument直接保存就可以了，何必循环遍历treeview再保存呢？

------解决方案--------------------
http://www.cnblogs.com/wf5360308/articles/1227700.html