委托与委托的关键字

从http://msdn.microsoft.com/en-us/library/system.delegate.aspx:

在代理类的基类   对于委托类型。然而，只有   系统和编译器可以得到   明确从代理类或   从 MulticastDelegate 类。它   也不允许以导出   新型的委托类型。该   代理类不被认为是   委托类型;它是用一类   派生委托类型。

The Delegate class is the base class for delegate types. However, only the system and compilers can derive explicitly from the Delegate class or from the MulticastDelegate class. It is also not permissible to derive a new type from a delegate type. The Delegate class is not considered a delegate type; it is a class used to derive delegate types.

大多数语言实施代理   关键字，编译器对于那些   语言都能够从派生    MulticastDelegate 类;因此，   用户应使用代理关键词   由语言提供的。

Most languages implement a delegate keyword, and compilers for those languages are able to derive from the MulticastDelegate class; therefore, users should use the delegate keyword provided by the language.