C# WebApi遇到的坑之第二次請求失敗問題

最近做的一個WebApi項目，需要訪問別人的接口。寫好訪問POST請求的接口后，調試成功！

But，第二次請求就會超時！Why？？？

於是乎網上各種找方案，無奈就是找不到。怎么辦呢？於是把HttpWebRequest類的每一個屬性都設置一邊看看有沒有效果。

皇天不負有心人啊，終於找到了病症的症結所在····

不廢話了，貼代碼：

        /// <summary>
        /// POST請求
        /// </summary>
        /// <param name="url">地址</param>
        /// <param name="parameters">參數</param>
        /// <param name="timeOut">超時時間</param>
        /// <returns></returns>
        public static string HttpPost(string url, IDictionary<string, string> parameters, int timeOut)
        {
            HttpWebRequest request = null;
            request = WebRequest.Create(url) as HttpWebRequest;
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.Timeout = timeOut;//超時時間
            request.ServicePoint.Expect100Continue = false;//解決第二次請求失敗問題

            //發送POST數據  
            if (!(parameters == null || parameters.Count == 0))
            {
                StringBuilder buffer = new StringBuilder();
                int i = 0;
                foreach (string key in parameters.Keys)
                {
                    if (i > 0)
                    {
                        buffer.AppendFormat("&{0}={1}", key, parameters[key]);
                    }
                    else
                    {
                        buffer.AppendFormat("{0}={1}", key, parameters[key]);
                        i++;
                    }
                }
                byte[] data = Encoding.ASCII.GetBytes(buffer.ToString());
                using (Stream stream = request.GetRequestStream())
                {
                    stream.Write(data, 0, data.Length);
                }
            }
            string[] values = request.Headers.GetValues("Content-Type");

            HttpWebResponse response = (HttpWebResponse)request.GetResponse();

            using (Stream s = response.GetResponseStream())
            {
                StreamReader reader = new StreamReader(s, Encoding.UTF8);
                return reader.ReadToEnd();
            }
        }        

 

關鍵點就在於設置一個屬性為false：request.ServicePoint.Expect100Continue = false;