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I want to upload text & files from a desktop application in c# to a web server (running i php),

So I try this code :

In C# :

string URL = "http://localhost/TestUploadFile.php";
string boundary = "----------------------------" + DateTime.Now.Ticks.ToString("x");
WebRequest webRequest = WebRequest.Create(URL);
webRequest.Method = "POST";
webRequest.ContentType = "multipart/form-data; boundary=" + boundary;

Stream postDataStream = new MemoryStream();

//adding form data
string formDataHeaderTemplate = Environment.NewLine + "--" + boundary + Environment.NewLine + "Content-Disposition: form-data; name=\"{0}\";" + Environment.NewLine + Environment.NewLine + "{1}";
byte[] formItemBytes = Encoding.UTF8.GetBytes(string.Format(formDataHeaderTemplate, "value", "valueTest"));
postDataStream.Write(formItemBytes, 0, formItemBytes.Length);

//adding file data

string FilePath = @"C:\test\";

string[] files = Directory.GetFiles(FilePath);

for(int i = 0; i < files.Length; i++)
    FileInfo fileInfo = new FileInfo(files[i]);
    string fileHeaderTemplate = Environment.NewLine + "--" + boundary + Environment.NewLine + "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"" + Environment.NewLine + "Content-Type: application/octet-stream" + Environment.NewLine + Environment.NewLine;
    byte[] fileHeaderBytes = Encoding.UTF8.GetBytes(string.Format(fileHeaderTemplate, "UploadFile", fileInfo.FullName));
    postDataStream.Write(fileHeaderBytes, 0, fileHeaderBytes.Length);

    FileStream fileStream = fileInfo.OpenRead();

    byte[] bufferFiles = new byte[1024];

    int bytesRead = 0;

    while ((bytesRead = fileStream.Read(bufferFiles, 0, bufferFiles.Length)) != 0)
        postDataStream.Write(buffer, 0, bytesRead);


byte[] endBoundaryBytes = Encoding.UTF8.GetBytes("--" + boundary + "--");

postDataStream.Write(endBoundaryBytes, 0, endBoundaryBytes.Length);

webRequest.ContentLength = postDataStream.Length;

Stream reqStream = webRequest.GetRequestStream();

postDataStream.Position = 0;

byte[] buffer = new byte[1024];

int bytesRead = 0;

while ((bytesRead = postDataStream.Read(buffer, 0, buffer.Length)) != 0)
    reqStream.Write(buffer, 0, bytesRead);


StreamReader sr = new StreamReader(webRequest.GetResponse().GetResponseStream());
string Result = sr.ReadToEnd();


In my WebApplication (in php)


$uploaddir = 'upload/'; // Relative Upload Location of data file

if(isset($_FILES['file']['tmp_name'])) {
    if (is_uploaded_file($_FILES['file']['tmp_name'])) {

        $uploadfile = $uploaddir . basename($_FILES['file']['name']);
        echo 'File '. $_FILES['file']['name']. ' uploaded successfully';
        if ( move_uploaded_file($_FILES['file']['tmp_name'], $uploadfile) ) {
        echo "File is valid, and was successfully moved ";
    else {
else {
    echo "Upload Failed !!!";

if(isset($_POST['value'])) {
echo $_POST['value'];
else {
echo 'not value';

The MessageBox return "Failed" for upload files and the valueTest for form data (success for form data)

I think the problem is in the Content-Type: application/octet-stream !!! I want to upload all type of file (.txt, .pdf, .msg, ...)

I can't understand how to Content-Type work and I do not know the importance of boundary !!!

Can you help me please ?
Updated 7-Mar-21 14:21pm

1 solution


Boundary in Content Type : Link[^] go through this link it will clear your confusion.

Upload multiple files :

Before going to the code, your client code can upload multiple file only when your server code supports that but in your PHP code it looks like it can only accept single file.

public static void HttpUploadFile(string url, string file, string paramName, string contentType, NameValueCollection nvc) {
        string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
        byte[] boundarybytes = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "\r\n");

        HttpWebRequest wr = (HttpWebRequest)WebRequest.Create(url);
        wr.ContentType = "multipart/form-data; boundary=" + boundary;
        wr.Method = "POST";
        wr.KeepAlive = true;
        wr.Credentials = System.Net.CredentialCache.DefaultCredentials;

        Stream rs = wr.GetRequestStream();

        string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
        foreach (string key in nvc.Keys)
            rs.Write(boundarybytes, 0, boundarybytes.Length);
            string formitem = string.Format(formdataTemplate, key, nvc[key]);
            byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);
            rs.Write(formitembytes, 0, formitembytes.Length);
        rs.Write(boundarybytes, 0, boundarybytes.Length);

        string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n";
        string header = string.Format(headerTemplate, paramName, file, contentType);
        byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
        rs.Write(headerbytes, 0, headerbytes.Length);

        FileStream fileStream = new FileStream(file, FileMode.Open, FileAccess.Read);
        byte[] buffer = new byte[4096];
        int bytesRead = 0;
        while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0) {
            rs.Write(buffer, 0, bytesRead);

        byte[] trailer = System.Text.Encoding.ASCII.GetBytes("\r\n--" + boundary + "--\r\n");
        rs.Write(trailer, 0, trailer.Length);

        WebResponse wresp = null;
        try {
            wresp = wr.GetResponse();
            Stream stream2 = wresp.GetResponseStream();
            StreamReader reader2 = new StreamReader(stream2);
        } catch(Exception ex) {
            if(wresp != null) {
                wresp = null;
        } finally {
            wr = null;

Now you can call this code again again to upload multiple file.

You can use 'application/octet-stream'
Member 10872485 18-Aug-14 2:06am
Thank you Suvabrata Roy for your answer !
If I call this method, what can I put a paramName ?!
If I use application/octet-stream, I can upload all type of files ?! Or each type of file, there is a content type ???
Member 10872485 18-Aug-14 2:25am
I found this solution in : !?

I want to upload multi-files in one request :)
Suvabrata Roy 18-Aug-14 2:32am
Yes, I have copy it from there because your server code dos't support multiple file upload you need to modify that first then you can upload multiple files.

Member 10872485 18-Aug-14 7:08am
I just write :
in my server code, but it doesn't work !

I think that I have a problem in content_type !?

If I use application/octet-stream, I can upload all type off files (.csv, pdf, msg, .txt ) ???

Excuse me, but it's urgent !

Thank you in advance .
Suvabrata Roy 18-Aug-14 9:32am
Go through this link :

Excuse me : we are professionals so as on when we have spare time we will share our knowledge to help others.

Member 10872485 18-Aug-14 9:45am
I appreciate your knowledge to help others and thank you for your time :)

I am a beginner and I want to learn from a professionals developpers to become a professional after.

Thank you very much.
Suvabrata Roy 18-Aug-14 10:02am
Did your problem resolved?
Member 10872485 19-Aug-14 4:52am
Hi Suvabrata Roy, I left the office of my training when you asked me "Did your problem resolved?"

I found a solution on this link :

What is your view professional ?
Suvabrata Roy 19-Aug-14 7:19am
It works, you are using warping class rather then core code. Its nice use it.
WebClient will be very good for anonymous sites but not for authentication based sites.

I still wonder how your above mentioned PHP code will serve multiple files...
Member 10872485 20-Aug-14 6:04am
Yes, I'm using warping class then core code, this is HttpUploadHelper in UploadHelper library. It's advanced uploading with HttpWebRequest. This library provides an upload method that can upload multiple files and form variables in one request. But WebClient works for single file with no other form variables and you're right, it will be very good for anonymous sites but not for authentication based sites.

For testing my code, I just write (in php) :


After I will to apply it on a web application made ​​by the framework codeigniter.
Suvabrata Roy 20-Aug-14 6:33am
Ok, Best of luck. If you are going for wrapping class then I suggest you take view of this link :
Its HttpClient upgraded version of WebClient but you required .Net Framework 4.5 because its implement TPL ( Task Parallal Libery)
Member 10872485 20-Aug-14 10:33am
Thank you very much, I'm proud to learn from your experience and your knowledge :)

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