C# POST请求

        /// <summary>
        /// post请求带参数
        /// </summary>
        /// <param name="url"></param>
        /// <param name="param">参数字符串</param>
        /// <returns></returns>
        public static string Post(string url, string param)
        {
            //创建post请求
            HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
            request.Method = "POST";//请求方式post
            request.ContentType = "application/json;charset=UTF-8";//链接类型
            byte[] payload = Encoding.UTF8.GetBytes(param);//参数编码
            request.ContentLength = payload.Length;

            //发送post的请求,写入参数
            Stream writer = request.GetRequestStream();
            writer.Write(payload, 0, payload.Length);
            writer.Close();

            //接受返回来的数据
            HttpWebResponse response = request.GetResponse() as HttpWebResponse;
            Stream stream = response.GetResponseStream();
            StreamReader reader = new StreamReader(stream, Encoding.UTF8);
            string value = reader.ReadToEnd();

            reader.Close();
            stream.Close();
            response.Close();

            return value;
        }