winform调用api接口post方法

/// <summary>
        /// 调用WEBAPI方法
        /// </summary>
        /// <param name="url">地址</param>
        /// <param name="body">参数</param>
        /// <returns></returns>
        public static string HttpPost(string url, string body, string method = "POST")
        {
            try
            {
                Encoding encoding = Encoding.UTF8;
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
                request.Method = method;
                request.Accept = "text/html, application/xhtml+xml, */*";
                request.ContentType = "application/json";

                byte[] buffer = encoding.GetBytes(body);
                request.ContentLength = buffer.Length;
                if (method.Equals("POST"))
                {
                    request.GetRequestStream().Write(buffer, 0, buffer.Length);
                }
                HttpWebResponse response = (HttpWebResponse)request.GetResponse();
                using (StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.UTF8))
                {
                    return reader.ReadToEnd();
                }
            }
            catch (WebException ex)
            {

                HttpWebResponse response = (HttpWebResponse)ex.Response;
                if (response != null)
                {
                    Console.WriteLine("Error code: {0}", response.StatusCode);

                    using (StreamReader reader = new StreamReader(response.GetResponseStream(), System.Text.Encoding.Default))
                    {
                        string text = reader.ReadToEnd();

                        int start = text.IndexOf("System.Exception:");
                        string s = text.Substring(start, 2000);
                        throw new Exception("XX" + s);


                    }
                }
                else
                {
                    throw new Exception("XX" + ex.Message);
                }

            }
        }

实体类

 

string str = HttpHelper.HttpPost(url,“”);

调用