C#中XML和json互相转换

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Xml;
using Newtonsoft;//此方法需单独下载

namespace ThumbsLotteryTicket.MyMethond
{
    public class XML_JSON
    {
        /// <summary>
        /// 返回指定节点下信息的JSON格式字符串
        /// </summary>
        /// <param name="str">xml字符串</param>
        /// <param name="nodename">节点名称，应从根节点开始</param>
        /// <returns></returns>
        public string XML2Json(string str,string nodename)
        {
            string result = null;
            XmlDocument xmldoc = new XmlDocument();
            xmldoc.LoadXml(str);
            XmlNode node = xmldoc.SelectSingleNode(nodename);
            result = Newtonsoft.Json.JsonConvert.SerializeXmlNode(node);
            return result;
        }

        public string Json2XML(string str)
        {
            string result = null;
            XmlDocument xml = Newtonsoft.Json.JsonConvert.DeserializeXmlNode(str);
            result = xml.OuterXml;
            return result;
        }
    }