#region 根据xml节点 查询xml节点的值并作修改
/// <summary>
/// 根据xml节点 查询xml节点的值并作修改
/// </summary>
/// <param name=\"fileName\">要加载的xml文件</param>
/// <param name=\"tagName\">xml节点的名称</param>
/// <param name=\"newXmlText\">修改后的值</param>
/// <returns></returns>
public void GetXmlbySelNodel(string fileName, string selNodeName, string tagName,string newXmlText)
{
  try
  {
   doc.Load(Server.MapPath(fileName));
   XmlNodeList nodelist = doc.DocumentElement.SelectSingleNode(selNodeName).ChildNodes;
   foreach (XmlNode node in nodelist)
   {
    XmlElement xle = node as XmlElement;
    XmlNodeList list = xle.ChildNodes;
    for (int j = 0; j < list.Count; j++) {
     if (xle.ChildNodes[j].Name == tagName) {
      xle.ChildNodes[j].InnerText = newXmlText;
      SaveXml(fileName);
      break;
     }
    }
   }
  }
  catch { 
  }
}
#endregion
#region 保存修改后xml文件内容
//保存修改后xml文件内容
public void SaveXml(string fileName)
{
  doc.Save(Server.MapPath(fileName));
}
#endregion
string selNodeName=\"//url/data\";
string fileName = \"meituanAPI.xml\";
GetXmlbySelNodel(fileName, selNodeName, \"website\", \"phpstudy\");
GetXmlbySelNodel(fileName, selNodeName, \"siteurl\", \"www.phpstudy.net\");
GetXmlbySelNodel(fileName, selNodeName, \"city\", \"杭州\");
GetXmlbySelNodel(fileName, selNodeName, \"tip\", \"送ipad 抽奖!!\");
GetXmlbySelNodel(fileName, \"//data/shops\", \"name\", \"上海洲信 信息技术有限公司!\");
DataSet ds = new DataSet();
ds.ReadXml(Server.MapPath(\"meituanAPI.xml\"));
XmlTextWriter writer = new XmlTextWriter(Response.OutputStream, Response.ContentEncoding);
ds.Tables[0].WriteXml(writer);
Response.ContentType = \"text/xml;charset=gb2312\";
Response.Flush();
Response.End()

Response.ClearContent();
Response.ClearHeaders();
Response.contentType=\"application/xml\"\';
Response.WriterFile(Server.Mappath(\"API/54tuanAPI.xml\"));
Response.Flush();
Response.End();