protected void Page_Load(object sender, EventArgs e)

{          

　　　　string padata = "username=用户名&pwd=md5的密码&imgcode=&f=json";//用于登录要发送的数据

            string url = " ";//请求登录的URL

            try

            {

                CookieContainer cc = new CookieContainer();//接收缓存

                byte[] byteArray = Encoding.UTF8.GetBytes(padata); // 转化

                HttpWebRequest webRequest2 = (HttpWebRequest)WebRequest.Create(url);

                webRequest2.CookieContainer = cc;

                webRequest2.Method = "POST";

                webRequest2.ContentType = "application/x-www-form-urlencoded";

　　　　　　webRequest2.Referer = "https://mp.weixin.qq.com/";

                webRequest2.ContentLength = byteArray.Length;

                Stream newStream = webRequest2.GetRequestStream();

                    // Send the data.

                newStream.Write(byteArray, 0, byteArray.Length);    //写入参数

                newStream.Close();

                HttpWebResponse response2 = (HttpWebResponse)webRequest2.GetResponse();

                StreamReader sr2=new StreamReader(response2.GetResponseStream(), Encoding.Default);

                string text2 = sr2.ReadToEnd();            

                //此处用到了newtonsoft来序列化。大家可以不用这个，也可以自己手动写代码

                RetInfo retinfo=Newtonsoft.Json.JsonConvert.DeserializeObject<RetInfo>(text2);

                string token = retinfo.ErrMsg.Split(new char[] { '&' })[2].Split(new char[]{'='})[1].ToString();//取得令牌

                SendMessage(cc,token);

            }

            catch (Exception ex)

            {

                throw new Exception(ex.StackTrace);

            }

}

public void SendMessage(CookieContainer cc, string token)        

{                       

　　 string padate = "type=1&content=要发送的内容（注意要先进行Url编码）&error=false&tofakeid=22108785&token=" + token + "&ajax=1";  

       string url = "";

        byte[] byteArray = Encoding.UTF8.GetBytes(padate); // 转化

        HttpWebRequest webRequest2 = (HttpWebRequest)WebRequest.Create(url);

        webRequest2.CookieContainer = cc; //登录时得到的缓存

        webRequest2.Referer = "=" + token + "&fromfakeid=22108785&msgid=&source=&count=20&t=wxm-singlechat&lang=zh_CN";

       webRequest2.Method = "POST";

       webRequest2.UserAgent = "Mozilla/5.0 (Windows NT 5.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1";

        webRequest2.ContentType = "application/x-www-form-urlencoded";

         webRequest2.ContentLength = byteArray.Length; 

         Stream newStream = webRequest2.GetRequestStream();

        // Send the data.            

     newStream.Write(byteArray, 0, byteArray.Length);    //写入参数    

     newStream.Close();

     HttpWebResponse response2 = (HttpWebResponse)webRequest2.GetResponse();

     StreamReader sr2 = new StreamReader(response2.GetResponseStream(), Encoding.Default);

    string text2 = sr2.ReadToEnd();  

    Response.Write(text2);  

}