用来学习很不错的一个VC++小实例，使用树形菜单控件操作数据库，类似Windows资源管理器的模式，每点击菜单的某一项，数据库对应项就会被重新加载。-Used to study a very good example of VC++ small, use the tree menu control to operate the database, similar to Windows Explorer model, each click on a menu, the corresponding