Question

介绍代表的主要理由是什么,也是哪类问题的解决办法。她想知道这一问题。预收

Answer 1

您可认为代表与单一方法的接口一样。因此,在没有代表的语文(如 Java)使用接口的地方,有代表是明智的。

代表对界面享有这些福利:

The implementation can be private, whereas methods implementing interfaces have to be public in Java. (C# has explicit interface implementation as well.)
You can implement multiple delegates in a single class, or even the same delegate type multiple times
The framework and language have additional support for delegates:
- Combining them together (and removing them)
- A pub/sub framework (events)
- Background invocation using the thread pool (BeginInvoke etc)
- Lambda expressions and anonymous methods make them easy to create "inline"
- Expression trees, representing the logic of an expression in data rather than IL

代表通常用于:

想把它们当作一种方式来概括一种单一的行为,看看它如何引导你们。