public static class HttpHelper{private static readonly Encoding DEFAULTENCODE = Encoding.UTF8;/// <summary>/// HttpUploadFile/// </summary>/// <param name="url"></param>/// <param name="file"></param>/// <param name="data"></param>/// <returns></returns>public static string HttpUploadFile(string url, string file, NameValueCollection data){return HttpUploadFile(url, file, data, DEFAULTENCODE);}/// <summary>/// HttpUploadFile/// </summary>/// <param name="url"></param>/// <param name="file"></param>/// <param name="data"></param>/// <param name="encoding"></param>/// <returns></returns>public static string HttpUploadFile(string url, string file, NameValueCollection data, Encoding encoding){return HttpUploadFile(url, new string[] { file }, data, encoding);}/// <summary>/// HttpUploadFile/// </summary>/// <param name="url"></param>/// <param name="files"></param>/// <param name="data"></param>/// <returns></returns>public static string HttpUploadFile(string url, string[] files, NameValueCollection data){return HttpUploadFile(url, files, data, DEFAULTENCODE);}/// <summary>/// HttpUploadFile/// </summary>/// <param name="url"></param>/// <param name="files"></param>/// <param name="data"></param>/// <param name="encoding"></param>/// <returns></returns>public static string HttpUploadFile(string url, string[] files, NameValueCollection data, Encoding encoding){string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");byte[] boundarybytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");byte[] endbytes = Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");//1.HttpWebRequestHttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);request.ContentType = "multipart/form-data; boundary=" + boundary;request.Method = "POST";request.KeepAlive = true;request.Credentials = CredentialCache.DefaultCredentials;using (Stream stream = request.GetRequestStream()){//1.1 key/valuestring formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";if (data != null){foreach (string key in data.Keys){stream.Write(boundarybytes, 0, boundarybytes.Length);string formitem = string.Format(formdataTemplate, key, data[key]);byte[] formitembytes = encoding.GetBytes(formitem);stream.Write(formitembytes, 0, formitembytes.Length);}}//1.2 filestring headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: application/octet-stream\r\n\r\n";byte[] buffer = new byte[4096];int bytesRead = 0;for (int i = 0; i < files.Length; i++){stream.Write(boundarybytes, 0, boundarybytes.Length);string header = string.Format(headerTemplate, "file" + i, Path.GetFileName(files[i]));byte[] headerbytes = encoding.GetBytes(header);stream.Write(headerbytes, 0, headerbytes.Length);using (FileStream fileStream = new FileStream(files[i], FileMode.Open, FileAccess.Read)){while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0){stream.Write(buffer, 0, bytesRead);}}}//1.3 form endstream.Write(endbytes, 0, endbytes.Length);}//2.WebResponseHttpWebResponse response = (HttpWebResponse)request.GetResponse();using (StreamReader stream = new StreamReader(response.GetResponseStream())){return stream.ReadToEnd();}}}

    <httpRuntime executionTimeout="10" maxRequestLength="51200"useFullyQualifiedRedirectUrl="true" minFreeThreads="8"minLocalRequestFreeThreads="4" appRequestQueueLimit="100"  enableVersionHeader="true"/>