一个Ftp传输类，有进度条，通过回调设置进度条-Ftp transfer of a class, there is a progress bar, progress bar by setting a callback

使用wininet开发的FTP封装类，接口功能齐全，可以实现文件上传、下载，支持多线程，进度显示等功能，已经验证过，非常好用-Wininet developed using FTP wrapper classes, interfaces fully functional, can achieve file upload, download, support for multithreading, progress display and