Upload files with HTTPWebrequest (multipart/form-data)

Question

Is there any class, library or some piece of code which will help me to upload files with HTTPWebrequest?

Edit 2:

I do not

Answer 1

UPDATE: Using .NET 4.5 (or .NET 4.0 by adding the Microsoft.Net.Http package from NuGet) this is possible without external code, extensions, and "low level" HTTP manipulation. Here is an example:

// Perform the equivalent of posting a form with a filename and two files, in HTML:
// 

//     
//     
//     
// 
private async Task UploadAsync(string url, string filename, Stream fileStream, byte [] fileBytes)
{
    // Convert each of the three inputs into HttpContent objects

    HttpContent stringContent = new StringContent(filename);
    // examples of converting both Stream and byte [] to HttpContent objects
    // representing input type file
    HttpContent fileStreamContent = new StreamContent(fileStream);
    HttpContent bytesContent = new ByteArrayContent(fileBytes);

    // Submit the form using HttpClient and 
    // create form data as Multipart (enctype="multipart/form-data")

    using (var client = new HttpClient())
    using (var formData = new MultipartFormDataContent()) 
    {
        // Add the HttpContent objects to the form data

        // 
        formData.Add(stringContent, "filename", "filename");
        // 
        formData.Add(fileStreamContent, "file1", "file1");
        // 
        formData.Add(bytesContent, "file2", "file2");

        // Invoke the request to the server

        // equivalent to pressing the submit button on
        // a form with attributes (action="{url}" method="post")
        var response = await client.PostAsync(url, formData);

        // ensure the request was a success
        if (!response.IsSuccessStatusCode)
        {
            return null;
        }
        return await response.Content.ReadAsStreamAsync();
    }
}