HttpWebRequest模拟登陆，存储Cookie以便登录请求后使用

[一篮饭特稀原创，转载请注明出自http://www.cnblogs.com/wanghafan/p/3284481.html]

PostLogin ：登录，并保存Cookie

 public static string PostLogin(string postData, string requestUrlString, ref CookieContainer cookie)
    {
        ASCIIEncoding encoding = new ASCIIEncoding();
        byte[] data = encoding.GetBytes(postData);
        //向服务端请求
        HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(requestUrlString);
        myRequest.Method = "POST";
        myRequest.ContentType = "application/x-www-form-urlencoded";
        myRequest.ContentLength = data.Length;
        myRequest.CookieContainer = new CookieContainer();
        Stream newStream = myRequest.GetRequestStream();
        newStream.Write(data, 0, data.Length);
        newStream.Close();
        //将请求的结果发送给客户端(界面、应用)
        HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
        cookie.Add(myResponse.Cookies);
        StreamReader reader = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);
        return reader.ReadToEnd();
    }

PostRequest ：登录后使用Cookie进行其他操作

 public static string PostRequest(string postData, string requestUrlString, CookieContainer cookie)
    {
        ASCIIEncoding encoding = new ASCIIEncoding();
        byte[] data = encoding.GetBytes(postData);
        HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(requestUrlString);
        myRequest.Method = "POST";
        myRequest.ContentType = "application/x-www-form-urlencoded";        
        myRequest.ContentLength = data.Length;
        myRequest.CookieContainer = cookie;
        Stream newStream = myRequest.GetRequestStream();
        newStream.Write(data, 0, data.Length);
        newStream.Close();
        HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
        StreamReader reader = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);
        return reader.ReadToEnd();
    }

e.g.

            string strIMSPhone = tb_IMSPhone.Text.Trim();
            string strIMSPwd = tb_IMSPwd.Text.Trim();
            string postData = "username=" + strIMSPhone + "&password=" + strIMSPwd + "&type=2";
            CookieContainer cookie=new CookieContainer();
            if (IMSHelper.PostLogin(postData, post_signIn, ref cookie).Equals("ok"))
            {
                string strCont = PostRequest("", post_getContJsonData, cookie);    
            }