Hi, guys, first of all thanks for your contributions, I've found great responses here. Yet I've ran into a problem I can't figure out and if someone could provide any help, it would be greatly appreciated.

I'm developing this application in C# that could upload an image from computer to user photoblog. For this I'm usig pixelpost platform for photoblogs that is written mainly in PHP.

I've searched here and on other web pages, but the exmples provided there didn't work for me. Here is what I used in my example: (http://stackoverflow.com/questions/566462/upload-files-with-httpwebrequest-multipart-form-data) and (http://bytes.com/topic/c-sharp/answers/268661-how-upload-file-via-c-code) Once it is ready I will make it available for free on the internet and maybe also create a windows mobile version of it, since I'm a fan of pixelpost.

here is the code I've used:

        string formUrl = "http://localhost/pixelpost/admin/index.php?x=login";
        string formParams = string.Format("user={0}&password={1}", "user-String", "password-String");
        string cookieHeader;
        HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(formUrl);
        req.ContentType = "application/x-www-form-urlencoded";
        req.Method = "POST";
        req.AllowAutoRedirect = false;
        byte[] bytes = Encoding.ASCII.GetBytes(formParams);
        req.ContentLength = bytes.Length;
        using (Stream os = req.GetRequestStream())
        {
            os.Write(bytes, 0, bytes.Length);
        }
        HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
        cookieHeader = resp.Headers["Set-Cookie"];

        string pageSource;
        using (StreamReader sr = new StreamReader(resp.GetResponseStream()))
        {
            pageSource = sr.ReadToEnd();
            Console.WriteLine();
        }

        string getUrl = "http://localhost/pixelpost/admin/index.php";
        HttpWebRequest getRequest = (HttpWebRequest)HttpWebRequest.Create(getUrl);
        getRequest.Headers.Add("Cookie", cookieHeader);
        HttpWebResponse getResponse = (HttpWebResponse)getRequest.GetResponse();
        using (StreamReader sr = new StreamReader(getResponse.GetResponseStream()))
        {
            pageSource = sr.ReadToEnd();
        }

        // end first part: login to admin panel

        long length = 0;
        string boundary = "----------------------------" +
        DateTime.Now.Ticks.ToString("x");

        HttpWebRequest httpWebRequest2 = (HttpWebRequest)WebRequest.Create("http://localhost/pixelpost/admin/index.php?x=save");
        httpWebRequest2.ContentType = "multipart/form-data; boundary=" + boundary;
        httpWebRequest2.Method = "POST";
        httpWebRequest2.AllowAutoRedirect = false; 
        httpWebRequest2.KeepAlive = false;
        httpWebRequest2.Credentials = System.Net.CredentialCache.DefaultCredentials;
        httpWebRequest2.Headers.Add("Cookie", cookieHeader);



        Stream memStream = new System.IO.MemoryStream();

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


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

        string formitem = string.Format(formdataTemplate, "headline", "image-name");
        byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);
        memStream.Write(formitembytes, 0, formitembytes.Length);

        memStream.Write(boundarybytes, 0, boundarybytes.Length);


        string headerTemplate = "\r\nContent-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: application/octet-stream\r\n\r\n";



        string header = string.Format(headerTemplate, "userfile", "path-to-the-local-file");

        byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);

        memStream.Write(headerbytes, 0, headerbytes.Length);


        FileStream fileStream = new FileStream("path-to-the-local-file", FileMode.Open, FileAccess.Read);
        byte[] buffer = new byte[1024];

        int bytesRead = 0;

        while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
        {
            memStream.Write(buffer, 0, bytesRead);

        }

        memStream.Write(boundarybytes, 0, boundarybytes.Length);

        fileStream.Close();


        httpWebRequest2.ContentLength = memStream.Length;

        Stream requestStream = httpWebRequest2.GetRequestStream();

        memStream.Position = 0;
        byte[] tempBuffer = new byte[memStream.Length];
        memStream.Read(tempBuffer, 0, tempBuffer.Length);
        memStream.Close();
        requestStream.Write(tempBuffer, 0, tempBuffer.Length);
        requestStream.Close();


        WebResponse webResponse2 = httpWebRequest2.GetResponse();

        Stream stream2 = webResponse2.GetResponseStream();
        StreamReader reader2 = new StreamReader(stream2);


        Console.WriteLine(reader2.ReadToEnd());

        webResponse2.Close();
        httpWebRequest2 = null;
        webResponse2 = null;

and also here is the PHP: (http://dl.dropbox.com/u/3149888/index.php) and (http://dl.dropbox.com/u/3149888/new_image.php)

the mandatory fields are headline and userfile so I can't figure out where the mistake is, as the format sent in right. I'm guessing there is something wrong with the octet-stream sent to the form. Maybe it's a stupid mistake I wasn't able to trace, in any case, if you could help me that would mean a lot.

thanks,