string filePath = "E:\\test.rar";
            string fileName = "test.rar";
            string postURL = "http://localhost:5995/Default.aspx";

            // 边界符  
            var boundary = "---------------" + DateTime.Now.Ticks.ToString("x");
            var beginBoundary = Encoding.ASCII.GetBytes("--" + boundary + "\r\n");
            var fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read);

            // 最后的结束符  
            var endBoundary = Encoding.ASCII.GetBytes("--" + boundary + "--\r\n");

            // 文件参数头  
            const string filePartHeader =
                "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\n" +
                 "Content-Type: application/octet-stream\r\n\r\n";
            var fileHeader = string.Format(filePartHeader, "file", fileName);
            var fileHeaderBytes = Encoding.UTF8.GetBytes(fileHeader);

            // 开始拼数据  
            var memStream = new MemoryStream();
            memStream.Write(beginBoundary, 0, beginBoundary.Length);

            // 文件数据  
            memStream.Write(fileHeaderBytes, 0, fileHeaderBytes.Length);
            var buffer = new byte[1024];
            int bytesRead; // =0  
            while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
            {
                memStream.Write(buffer, 0, bytesRead);
            }
            fileStream.Close();

            // Key-Value数据  
            var stringKeyHeader = "\r\n--" + boundary +
                                   "\r\nContent-Disposition: form-data; name=\"{0}\"" +
                                   "\r\n\r\n{1}\r\n";

            Dictionary<string, string> stringDict = new Dictionary<string, string>();
            stringDict.Add("len", "500");
            stringDict.Add("wid", "300");
            foreach (byte[] formitembytes in from string key in stringDict.Keys
                                             select string.Format(stringKeyHeader, key, stringDict[key])
                                                 into formitem
                                                 select Encoding.UTF8.GetBytes(formitem))
            {
                memStream.Write(formitembytes, 0, formitembytes.Length);
            }

            // 写入最后的结束边界符  
            memStream.Write(endBoundary, 0, endBoundary.Length);

            //倒腾到tempBuffer?  
            memStream.Position = 0;
            var tempBuffer = new byte[memStream.Length];
            memStream.Read(tempBuffer, 0, tempBuffer.Length);
            memStream.Close();

            // 创建webRequest并设置属性  
            var webRequest = (HttpWebRequest)WebRequest.Create(postURL);
            webRequest.Method = "POST";
            webRequest.Timeout = 100000;
            webRequest.ContentType = "multipart/form-data; boundary=" + boundary;
            webRequest.ContentLength = tempBuffer.Length;

            var requestStream = webRequest.GetRequestStream();
            requestStream.Write(tempBuffer, 0, tempBuffer.Length);
            requestStream.Close();

            var httpWebResponse = (HttpWebResponse)webRequest.GetResponse();
            string responseContent;
            using (var httpStreamReader = new StreamReader(httpWebResponse.GetResponseStream(), Encoding.GetEncoding("utf-8")))
            {
                responseContent = httpStreamReader.ReadToEnd();
            }

            httpWebResponse.Close();
            webRequest.Abort();

  Response.ContentType = "text/plain";
        if (Request.Files.Count == 0)
        {
            Response.Write("No file");
            return;
        }

        HttpPostedFile f1 = Request.Files[0];
        f1.SaveAs("E:\\test-upload.rar");

string strPars = "";
foreach (var key in Request.Form.AllKeys)
{
 string val = Request[key];
 strPars += "[" + key + ":" + val + "] ";
}
image.Dispose();
Response.Write("OK Get File:" + f1.FileName + " Pars:" + strPars);