Chilkat FTP C++ Library 

FTP C++ class library to upload/download/delete files. Get FTP directory listing, upload directory trees with restart, xfer to/from memory, create/delete remote dirs, session logging, MGET/MPUT, proxy support, active/passive, binary/ascii modes.
ftp class library c++ sdk api protocol

Xceed FTP Library 

The Xceed FTP Library is a high-performance ActiveX control that allows developers to easily add FTP capabilities to their Windows or Web based applications and provides complete access to the feature rich and firewall friendly FTP protocol.
ftp asp ftp component ftp control ftp delphi ftp dll ftp library ftp ocx ftp vb ftp activex ftp .net ftp vb.net ftp c# ftp j#