Setting port in FtpWebRequest

I need the user to be able to be able to modify the port for downloading FTP information 开发者_Python百科- but I can't find a way of changing this in FtpWebRequest.

Isn't the port just part of the URI used to create the web request?

FtpWebRequest request = (FtpWebRequest)WebRequest.Create("ftp://10.0.0.1:12345");