Http Post

        public static async Task<string> PostFormUrlEncoded(string url, IEnumerable<KeyValuePair<string, string>> postData)
        {
            using (var httpClient = new HttpClient())
            {
                using (var content = new FormUrlEncodedContent(postData))
                {
                    content.Headers.Clear();
                    content.Headers.Add("Content-Type", "application/x-www-form-urlencoded");

                    HttpResponseMessage response = await httpClient.PostAsync(url, content);

                    return await response.Content.ReadAsStringAsync();
                }
            }
        }

        //public static string HttpPostForm(string url, IEnumerable<KeyValuePair<string, string>> pairs)
        //{
        //    var client = new RestClient(url);
        //    client.Timeout = 20 * 1000;
        //    var request = new RestRequest(Method.POST);
        //    request.AddHeader("Content-Type", "application/x-www-form-urlencoded");
        //    foreach (var pair in pairs)
        //    {
        //        request.AddParameter(pair.Key, pair.Value);
        //    }
        //    IRestResponse response = client.Execute(request);
        //    return response.Content;
        //}

        public static string HttpPostFrom(string url, string data)
        {
            string htmlAll = "";
            try
            {
                string SendMessageAddress = url;//请求链接
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(SendMessageAddress);
                request.Method = "POST";
                request.AllowAutoRedirect = true;
                request.Timeout = 20 * 1000;
                request.ContentType = "application/x-www-form-urlencoded";
                request.Headers.Add("x-cherun-auth-key", "LarxMbndsxfGwoYAqsfJSPPU42l04cb3");
                //string PostData = "a=1&b=2";//请求参数格式
                string PostData = data;//请求参数
                byte[] byteArray = Encoding.Default.GetBytes(PostData);
                request.ContentLength = byteArray.Length;
                using (Stream newStream = request.GetRequestStream())
                {
                    newStream.Write(byteArray, 0, byteArray.Length);//写入参数
                    newStream.Close();
                }

                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                Stream rspStream = response.GetResponseStream();
                using (StreamReader reader = new StreamReader(rspStream, Encoding.UTF8))
                {
                    htmlAll = reader.ReadToEnd();
                    rspStream.Close();
                }
                response.Close();
            }
            catch (Exception ex)
            {

                string s = ex.Message;
            }
            return htmlAll;
        }