Mit C sharp eine csv Datei an ein PHP script senden

<?php
require_once './classes/account/class.accountdao.php';  
if (isset($_POST["username"]) && isset($_POST["token"]) && isset($_POST["service"])) {  
    $response = AccountDAO::doServiceLogin($_POST["username"], $_POST["token"]);  
    switch ($response) {
        case 1:
            echo "Benutzername oder Passwort falsch!";  
            break;
        case 2:
            echo "Programmlaufzeit erloschen. Bitte kontaktieren Sie Ihren Service!";  
            break;
        case 0:
            
            if ($_POST["service"] == 3) {  
                echo "OK";  
            } else if ($_POST["service"] == 2 || $_POST["service"] == 1) {  
                
                // Artikel || Warengruppen Upload
               
                if(!empty($_FILES["updatefile"]) && $_FILES["updatefile"]["error"] ==0){  
                    $csvAsArray = array_map('str_getcsv', file($_FILES['updatefile']['tmp_name']));  
                    print_r($csvAsArray);
                    
                    
                    //TODO: CSV Datei in Datenbank einspielen
                    
                    
                    
                    AccountDAO::updateLastServiceUpdate($_POST["username"]);  
                }else{
                    echo "Parameter nicht gesetzt";  
                }        
            } else {
                echo "Parameter nicht gesetzt";  
            }
            break;
    }
} else
    echo "Parameter nicht gesetzt";  

?>

string URL = ConfigurationManager.AppSettings["SrvAdr"];  
            WebClient webClient = new WebClient();
            string boundaryString = "--------------";  
            NameValueCollection formData = new NameValueCollection();
            formData["username"] = "icitsoftware";  
            formData["token"] = "ee977806d7286510da8b9a7492ba58e2484c0ecc";  
            formData["service"] = "3";  
            


            byte responseBytes = webClient.UploadValues(URL, "POST", formData);  
            MemoryStream postDataStream = new MemoryStream();
            StreamWriter postDataWriter = new StreamWriter(postDataStream);

 string responsefromserver = Encoding.UTF8.GetString(responseBytes);
            
            MessageBox.Show(responsefromserver);
            webClient.Dispose();

NameValueCollection formData = new NameValueCollection(); 

            formData["username"] = "username";   

            formData["token"] = "passwordtoken";   

            formData["service"] = "3";   

HttpWebRequest requestToServerEndpoint =
            (HttpWebRequest)WebRequest.Create("http://www.you-order.it/testfile.php");  

            string boundaryString = "----SomeRandomText";  
            string fileUrl = @"C:\artikel.csv";  

            // Set the http request header 
        
            requestToServerEndpoint.Method = WebRequestMethods.Http.Post;
            requestToServerEndpoint.ContentType = "multipart/form-data; boundary=" + boundaryString;  
            requestToServerEndpoint.KeepAlive = true;
            requestToServerEndpoint.Credentials = System.Net.CredentialCache.DefaultCredentials;
            

            // Use a MemoryStream to form the post data request,
            // so that we can get the content-length attribute.
            MemoryStream postDataStream = new MemoryStream();
            StreamWriter postDataWriter = new StreamWriter(postDataStream);

            // Include value from the myFileDescription text area in the post data
           
            postDataWriter.Write("\r\n--" + boundaryString + "\r\n");  
            postDataWriter.Write("Content-Disposition:form-data; name=\"{0}\"\r\n\r\n{1}",  
            "updatefile",  
            "artikel");  

            // Include the file in the post data
            postDataWriter.Write("\r\n--" + boundaryString + "\r\n");  
            postDataWriter.Write("Content-Disposition: form-data;"  
            + "name=\"{0}\";"  
            + "filename=\"{1}\""  
            + "\r\nContent-Type: {2}\r\n\r\n",  
            "updatefile",  
            Path.GetFileName(fileUrl),
            Path.GetExtension(fileUrl));
            postDataWriter.Flush();

            // Read the file
            FileStream fileStream = new FileStream(fileUrl, FileMode.Open, FileAccess.Read);
            byte buffer = new byte[1024];
            int bytesRead = 0;
            while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
            {
                postDataStream.Write(buffer, 0, bytesRead);
            }
            fileStream.Close();

            postDataWriter.Write("\r\n--" + boundaryString + "--\r\n");  
            postDataWriter.Flush();

            // Set the http request body content length
            requestToServerEndpoint.ContentLength = postDataStream.Length;

            // Dump the post data from the memory stream to the request stream
            using (Stream s = requestToServerEndpoint.GetRequestStream())
            {
                postDataStream.WriteTo(s);
            }
            postDataStream.Close();
            // Grab the response from the server. WebException will be thrown
            // when a HTTP OK status is not returned
            WebResponse response = requestToServerEndpoint.GetResponse();
            StreamReader responseReader = new StreamReader(response.GetResponseStream());
            string replyFromServer = responseReader.ReadToEnd();
            MessageBox.Show(replyFromServer);