使用HttpWebRequest post数据时要注意UrlEncode

        public HttpWebResponse GetResponse(string url)

        {

            var req = (HttpWebRequest)WebRequest.Create(url);

            req.CookieContainer = CookieContainer;

            if (Parameters.Count > 0)

            {

                req.UserAgent = "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.2; .NET CLR 1.1.4322; .NET CLR 2.0.50727)";

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

                req.Method = "POST";

                //data要UrlEncode

                var postData = string.Join("&", Parameters.Select(

                                               p =>

                                               string.Format("{0}={1}", p.Key,

                                                             System.Web.HttpUtility.UrlEncode(p.Value, Encoding))).ToArray());

                var data = Encoding.GetBytes(postData);

                req.ContentLength = data.Length;

                using (var sw = req.GetRequestStream())

                {

                    sw.Write(data, 0, data.Length);

                }

            }

            req.Timeout = 40 * 1000;

            var response = (HttpWebResponse)req.GetResponse();

            return response;

        }