一个VC环境下使用的树形导航菜单控件，外形上和普通的树菜没什么区别，本例的重点是教会你如何使用本控件与数据库结合-A VC for use in the navigation menu tree controls, and the general appearance of the tree menu makes no difference, in this case the focus is to teach you how to use the combination of the cont