利用Socket套接字创建基于对话框类的FTP工具。主要功能是在网络上的FTP服务器上，实现单线程下载，能够实现文件上传功能。-use Socket created based on the type dialog FTP tools. Its main function is on the network FTP server, the thread to achieve the download, upload documents to achieve functional.

c＃实现的ftp服务器端的源码，基于socket 编程实现，有一定的参考价值