C#模拟Http与Https请求框架类实例

        /// </summary>
        /// <param name="Url"></param>
        /// <param name="postDataStr"></param>
        /// <returns></returns>
        public string HttpGet(string Url, string Querydata)
        {
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url + (Querydata == "" ? "" : "?") + Querydata);
            request.Method = "GET";
            request.ContentType = "text/html;charset=UTF-8";
            request.CookieContainer = cookie;
            this.SetCertificatePolicy();
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
           // response.Cookies = cookie.GetCookies(response.ResponseUri);
            Stream myResponseStream = response.GetResponseStream();
            StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
            string retString = myStreamReader.ReadToEnd();
            myStreamReader.Close();
            myResponseStream.Close();
            return retString;
        }

        /// <summary>
        /// 获得响应中的图像
        /// </summary>
        /// <param name="url"></param>
        /// <returns></returns>
        public Stream GetResponseImage(string url)
        {
            Stream resst = null;
            try
            {