大家在使用TreeView时,总是对于级别管理不好做,现在写了这个示例,提供两种方法的级别管理,希望为有方面的需要的朋友提供帮助. -When you use TreeView is always good for the level of management to do, I write you this example, offers two methods of level management, want to have friends of their needs to prov