C# Post 使用（multipart/form-data）请求数据

<br>public static string HttpPostMultipartFormData(string url,  NameValueCollection kVDatas, string method = WebRequestMethods.Http.Post, string encoding= "UTF-8", int timeOut = -1)
           {
               string resultStr = "";
               try
               {
                   string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
                   byte[] boundarybytes = Encoding.GetEncoding(encoding).GetBytes("\r\n--" + boundary + "\r\n");
                   byte[] endbytes = Encoding.GetEncoding(encoding).GetBytes("\r\n--" + boundary + "--\r\n");
 
                   //1.HttpWebRequest
                   HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
                   request.ContentType = "multipart/form-data; boundary=" + boundary;
                   request.Method = method;
                   request.KeepAlive = true;
                   request.Timeout = timeOut;
 
              
                   using (Stream stream = request.GetRequestStream())
                   {
                       //1.1 key/value
                       string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
                       if (kVDatas != null)
                       {
                           foreach (string key in kVDatas.Keys)
                           {
                               stream.Write(boundarybytes, 0, boundarybytes.Length);
                               string formitem = string.Format(formdataTemplate, key, kVDatas[key]);
                               byte[] formitembytes = Encoding.GetEncoding(encoding).GetBytes(formitem);
                               stream.Write(formitembytes, 0, formitembytes.Length);
                           }
                       }
                       stream.Write(endbytes, 0, endbytes.Length);
                   }
                   //2.WebResponse
                   using (HttpWebResponse response = (HttpWebResponse)request.GetResponse()) 
                   {
                       using (StreamReader stream = new StreamReader(response.GetResponseStream()))
                       {
                           resultStr = stream.ReadToEnd();
                           
                       }
                   }
                    
 
               }
               catch (WebException ex)
               {
                   var errorSr = new StreamReader(ex.Response.GetResponseStream());
                   resultStr = errorSr.ReadToEnd();
               }
               return resultStr;
           }