In your given example program1, display method is defined in both base and sub classes and you are trying to invoke it with the sub class object.

在你给的例子程序1，显示的方法是在基站和子类的定义和你试图调用它的子类对象。

youdao

For ATL-based COM object classes, class View reads the COM map in the ATL class to display the relationship between the ATL class and any interfaces it implements.

对基于AT L的COM对象类，类视图读取atl类中的COM映射以显示AT l类和它实现的任何接口间的关系。

youdao

For ATL-based COM object classes, class View reads the COM map in the ATL class to display the relationship between the ATL class and any interfaces it implements.

对基于AT L的COM对象类，类视图读取atl类中的COM映射以显示AT l类和它实现的任何接口间的关系。

youdao