C# GET获取XML，然后寻找所需节点，修改成所需的值，再PUT发送_c# get请求传xml

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Windows.Forms;
using System.Net;

using System.Xml;
using System.Xml.Serialization;

using System.Text;
using System.Collections;

namespace RestClient
{
 public partial class ClientForm : Form
 {
  void MakeRequest()
  {
   ResponseTextBox.Text = "Please wait...";

   var url = UrlTextBox.Text;
   var method = VerbComboBox.Text;
   var requestBody = RequestBodyTextBox.Text;
            string reponseAsString = "";
            string xmlString = "";
   try
            {

                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
                request.Method = "GET";
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();

                XmlReader reader = new XmlTextReader(new StreamReader(response.GetResponseStream(), Encoding.Default));

                XmlDocument doc = new XmlDocument();
                doc.Load(reader);

                string param = "deviceName";  //待查找的字段
               
                XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);  //XML命名空间管理器
                nsmgr.AddNamespace("urn", "urn:psialliance-org");   //添加命名空间
                XmlNode sNode = doc.SelectSingleNode("//urn:"+param, nsmgr);  //查找param节点
        
                sNode.InnerText = "test";  //将节点的文本信息修改为test

                //将XmlDocument转为string
                MemoryStream stream = new MemoryStream(); 
                XmlTextWriter mywriter = new XmlTextWriter(stream, null);
                mywriter.Formatting = Formatting.None;
                doc.Save(mywriter);

                StreamReader sr = new StreamReader(stream, System.Text.Encoding.UTF8);
                stream.Position = 0;
                xmlString = sr.ReadToEnd();
               
                //MessageBox.Show(xmlString);
                reader.Close();

                response.Close();
                stream.Dispose();
                mywriter.Close();
             
                stream.Close();
                request.Abort();

                HttpWebRequest requestWrite = (HttpWebRequest)WebRequest.Create("http://192.168.1.100/PSIA/System/deviceInfo");
                requestWrite.Method = "PUT";
                SetBody(requestWrite, xmlString); //发送
                response = (HttpWebResponse)requestWrite.GetResponse();

            }
   catch (Exception ex)
   {
    reponseAsString += "ERROR: " + ex.Message;
   }
            ResponseTextBox.Text = reponseAsString;
  }

  void SetBody(HttpWebRequest request1, string requestBody)
  {
   
    using (Stream requestStream = request1.GetRequestStream())
    using (StreamWriter writer = new StreamWriter(requestStream))
    {
     writer.Write(requestBody);
                    MessageBox.Show(requestBody);
    }
  
  }

  public ClientForm()
  {
   InitializeComponent();
  }

  void ClientForm_Load(object sender, EventArgs e)
  {
   VerbComboBox.SelectedIndex = 0;
            UrlTextBox.Text = "http://192.168.1.100/PSIA/System/deviceInfo";
  }

  void ExecuteButton_Click(object sender, EventArgs e)
  {
   MakeRequest();
  }

  void UrlTextBox_KeyDown(object sender, KeyEventArgs e)
  {
   if (e.KeyCode == Keys.Enter)
   {
    MakeRequest();
    e.Handled = true;
   }
  }
 }
}