委托是一个协议(介面)，定义了许多物件可以实作的方法，为了接收来自其他物件的特定讯息。
A delegate is a protocol (interface) that defines methods that an object implements in order to receive specific messages from other objects.
委托是一个协议(介面)，定义了许多物件可以实作的方法，为了接收来自其他物件的特定讯息。
A delegate is a protocol (interface) that defines methods that an object implements in order to receive specific messages from other objects.
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