/// <summary>

     /// 文件上传至远程服务器

     /// </summary>

     /// <param name="url">远程服务地址</param>

     /// <param name="postedFile">上传文件</param>

     /// <param name="parameters">POST参数</param>

     /// <param name="cookieContainer">cookie</param>

     /// <param name="output">远程服务器响应字符串</param>

     public static void HttpPostFile(string url,

                                     System.Web.HttpPostedFile postedFile,

                                     Dictionary<string, object> parameters,

                                     CookieContainer cookieContainer,

                                     ref string output)

     {

         //1>创建请求

         HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);

         //2>Cookie容器

         request.CookieContainer = cookieContainer;

         request.Method = "POST";

         request.Timeout = ;

         request.Credentials = System.Net.CredentialCache.DefaultCredentials;

         request.KeepAlive = true;

         string boundary = "----------------------------" + DateTime.Now.Ticks.ToString("x");//分界线

         byte[] boundaryBytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");

         request.ContentType = "multipart/form-data; boundary=" + boundary; ;//内容类型

         //3>表单数据模板

         string formdataTemplate = "\r\n--" + boundary + "\r\nContent-Disposition: form-data; name=\"{0}\";\r\n\r\n{1}";

         //4>读取流

         byte[] buffer = new byte[postedFile.ContentLength];

         postedFile.InputStream.Read(buffer, , buffer.Length);

         //5>写入请求流数据

         string strHeader = "Content-Disposition:application/x-www-form-urlencoded; name=\"{0}\";filename=\"{1}\"\r\nContent-Type:{2}\r\n\r\n";

         strHeader = string.Format(strHeader,

                                  "filedata",

                                  postedFile.FileName,

                                  postedFile.ContentType);

         //6>HTTP请求头

         byte[] byteHeader = System.Text.ASCIIEncoding.ASCII.GetBytes(strHeader);

         try

         {

             using (Stream stream = request.GetRequestStream())

             {

                 //写入请求流

                 if (null != parameters)

                 {

                     foreach (KeyValuePair<string, object> item in parameters)

                     {

                         stream.Write(boundaryBytes, , boundaryBytes.Length);//写入分界线

                         byte[] formBytes = System.Text.Encoding.UTF8.GetBytes(string.Format(formdataTemplate, item.Key, item.Value));

                         stream.Write(formBytes, , formBytes.Length);

                     }

                 }

                 //6.0>分界线============================================注意：缺少次步骤，可能导致远程服务器无法获取Request.Files集合

                 stream.Write(boundaryBytes, , boundaryBytes.Length);

                 //6.1>请求头

                 stream.Write(byteHeader, , byteHeader.Length);

                 //6.2>把文件流写入请求流

                 stream.Write(buffer, , buffer.Length);

                 //6.3>写入分隔流

                 byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");

                 stream.Write(trailer, , trailer.Length);

                 //6.4>关闭流

                 stream.Close();

             }

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

             using (StreamReader reader = new StreamReader(response.GetResponseStream()))

             {

                 output = reader.ReadToEnd();

             }

             response.Close();

         }

         catch (Exception ex)

         {

             throw new Exception("上传文件时远程服务器发生异常！", ex);

         }

     }