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

Client use convert File to ToBase64String, after use Xml to promulgate to Server call, this server use File.WriteAllBytes(path,Convert.FromBase64String(dataFile_Client_sent)).

Good lucky!