微信判断请求是否来自公众账号用户名

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Text;
using System.Web;
using System.Web.Http;
using System.Web.Mvc;
using System.Web.Security;
using System.Xml;

namespace WEBapi.Controllers
{

    public class WechatController : ApiController
    {
        //define("TOKEN", "weixin");
        public string Token = "bill";

        [System.Web.Http.HttpPost]
        [System.Web.Http.HttpGet]
        public JsonResult Entry()
        {
            // Debug.WriteLine(Request.Content);

            HttpContextBase context = (HttpContextBase)Request.Properties["MS_HttpContext"];//获取传统context     
            HttpRequestBase request = context.Request;//定义传统request对象
            HttpResponseBase response = context.Response;
            if (string.IsNullOrEmpty(request.QueryString["echoStr"]))
            {
                response.End();
            }
            string echoStr = request.QueryString["echoStr"].ToString();
            if (checkSignature())
            {
                if (!string.IsNullOrEmpty(echoStr))
                {
                    response.Write(echoStr);
                   // response.Output.Write("hello");
                    response.End();
                }
            }

            return new JsonResult();
        }
        public bool checkSignature()
        {
            HttpContextBase context = (HttpContextBase)Request.Properties["MS_HttpContext"];//获取传统context     
            HttpRequestBase request = context.Request;//定义传统request对象

            string signature = request.QueryString["signature"].ToString();
            string timestamp = request.QueryString["timestamp"].ToString();
            string nonce = request.QueryString["nonce"].ToString();
            string[] ArrTmp = { Token, timestamp, nonce };
            Array.Sort(ArrTmp); //字典排序

            string tmpStr = string.Join("", ArrTmp); //使用指定的字符分隔
            //加密
            tmpStr = FormsAuthentication.HashPasswordForStoringInConfigFile(tmpStr, "SHA1");
            tmpStr = tmpStr.ToLower();
            if (tmpStr == signature)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
    }
}