c#发送http请求注意

这里要注意几个点：
第一就是编码，如果编码不对，容易中文乱码
第二就是ContentType 如果设置不对，有可能连方法都调试不进去（我api用的是MVC的普通controller）
第三就是paramData参数形式要与ContentType保持一致

        /// <summary>
        /// 发送POST请求
        /// </summary>
        /// <param name="postUrl">api</param>
        /// <param name="paramData">参数，一般是param1=1&m2=2这种形式</param>
        /// <param name="dataEncode">编码</param>
        /// <returns></returns>
        private string PostWebRequest(string postUrl, string paramData, Encoding dataEncode)
        {
            string ret = string.Empty;
            try
            {
                byte[] byteArray = dataEncode.GetBytes(paramData); //转化
                HttpWebRequest webReq = (HttpWebRequest)WebRequest.Create(new Uri(postUrl));
                webReq.Method = "POST";
                webReq.ContentType = "application/x-www-form-urlencoded";
                //webReq.ContentType = "application/json";
                webReq.ContentLength = byteArray.Length;
                Stream newStream = webReq.GetRequestStream();
                newStream.Write(byteArray, 0, byteArray.Length);//写入参数
                newStream.Close();
                HttpWebResponse response = (HttpWebResponse)webReq.GetResponse();
                StreamReader sr = new StreamReader(response.GetResponseStream(), Encoding.UTF8);
                ret = sr.ReadToEnd();
                sr.Close();
                response.Close();
                newStream.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
            return ret;
        }