给定一个对象的句柄，客户端可以在运行时利用安全的向下转型，来请求一个特定接口。

Given a handle to an object, clients can request a specific interface at runtime using a safe downcast.

youdao

给定一个对象的句柄，客户端可以在运行时利用安全的向下转型，来请求一个特定接口。

Given a handle to an object, clients can request a specific interface at runtime using a safe downcast.

youdao