这是一个支持多选的TreeCtrl。多选对于TreeCtrl来说是一个很实用的功能，但是微软的MFC开发小组确没有实现它，这个程序写了一个继承与CTreeCtrl的类实现了多选功能。-This is one more election support TreeCtrl. For more TreeCtrl election is a very practical function, But Microsoft's MFC development team did not realize it, This procedure was made with a succession CTreeCtrl the category of multi-functional election.