[csharp]

public static string MyUploader(string strFileToUpload, string strUrl, string strFileFormName, NameValueCollection querystring, CookieContainer cookies) 

        { 

string postdata; 

            postdata = "?"; 

if (querystring != null) 

            { 

foreach (string key in querystring.Keys) 

                { 

                    postdata += key + "=" + querystring.Get(key) + "&"; 

                } 

            } 

//Uri uri = new Uri(strUrl + postdata);

            Uri oUri = new Uri(strUrl + postdata); 

string strBoundary = "----------" + DateTime.Now.Ticks.ToString("x"); 

// The trailing boundary string

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

// The post message header

            StringBuilder sb = new StringBuilder(); 

            sb.Append("--"); 

            sb.Append(strBoundary); 

            sb.Append("\r\n"); 

            sb.Append("Content-Disposition: form-data; name=\""); 

            sb.Append(strFileFormName); 

            sb.Append("\"; filename=\""); 

            sb.Append(Path.GetFileName(strFileToUpload)); 

            sb.Append("\""); 

            sb.Append("\r\n"); 

            sb.Append("Content-Type: "); 

            sb.Append("application/octet-stream"); 

            sb.Append("\r\n"); 

            sb.Append("\r\n"); 

string strPostHeader = sb.ToString(); 

byte[] postHeaderBytes = Encoding.UTF8.GetBytes(strPostHeader); 

// The WebRequest

            HttpWebRequest oWebrequest = (HttpWebRequest)WebRequest.Create(oUri); 

//如果是发送HTTPS请求 

if (strUrl.StartsWith("https", StringComparison.OrdinalIgnoreCase)) 

            { 

                ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(CheckValidationResult); 

                oWebrequest = WebRequest.Create(oUri) as HttpWebRequest; 

                oWebrequest.ProtocolVersion = HttpVersion.Version10; 

            } 

else

            { 

                oWebrequest = WebRequest.Create(oUri) as HttpWebRequest; 

            } 

            oWebrequest.ContentType = "multipart/form-data; boundary=" + strBoundary; 

            oWebrequest.Method = "POST"; 

// This is important, otherwise the whole file will be read to memory anyway...

            oWebrequest.AllowWriteStreamBuffering = false; 

// Get a FileStream and set the final properties of the WebRequest

            FileStream oFileStream = new FileStream(strFileToUpload, FileMode.Open, FileAccess.Read); 

long length = postHeaderBytes.Length + oFileStream.Length + boundaryBytes.Length; 

            oWebrequest.ContentLength = length; 

            Stream oRequestStream = oWebrequest.GetRequestStream(); 

// Write the post header

            oRequestStream.Write(postHeaderBytes, 0, postHeaderBytes.Length); 

// Stream the file contents in small pieces (4096 bytes, max).

byte[] buffer = new Byte[checked((uint)Math.Min(4096, (int)oFileStream.Length))]; 

int bytesRead = 0; 

while ((bytesRead = oFileStream.Read(buffer, 0, buffer.Length)) != 0) 

                oRequestStream.Write(buffer, 0, bytesRead); 

            oFileStream.Close(); 

// Add the trailing boundary

            oRequestStream.Write(boundaryBytes, 0, boundaryBytes.Length); 

            WebResponse oWResponse = oWebrequest.GetResponse(); 

            Stream s = oWResponse.GetResponseStream(); 

            StreamReader sr = new StreamReader(s); 

            String sReturnString = sr.ReadToEnd(); 

// Clean up

            oFileStream.Close(); 

            oRequestStream.Close(); 

            s.Close(); 

            sr.Close(); 

return sReturnString; 

        }