在C#中实现多态性，如何做到最好? [英] implementing polymorphism in c#, how best to do it?

问题描述

这里的第一个问题，希望大家都能对我轻描淡写！

first question here, so hopefully you'll all go gently on me!

过去几天，我一直在阅读有关多态性的大量文章，并尝试将其应用于我在c#中所做的事情，并且似乎有几种不同的方法来实现它.我希望我能解决这个问题，但是即使我没有澄清，我也会很高兴.

I've been reading an awful lot over the past few days about polymorphism, and trying to apply it to what I do in c#, and it seems there are a few different ways to implement it. I hope I've gotten a handle on this, but I'd be delighted even if I haven't for clarification.

据我所知，我有3种选择:

From what I can see, I've got 3 options:

1. 我可以从一个基础继承 类并使用关键字 我使用的任何方法上的"virtual" 希望我的派生类 覆盖.
2. 我可以使用虚拟方法实现抽象类 并这样做，
3. 我可以使用界面吗?

1. I can just inherit from a base class and use the keyword 'virtual' on any methods that I want my derived classes to override.
2. I could implement an abstract class with virtual methods and do it that way,
3. I could use an interface?

据我所见，如果我不需要任何基础实现逻辑，那么接口可以为我提供最大的灵活性(因为这样我就不会在多重继承等方面限制自己了)，但是如果我要求基础能够在派生类正在执行的操作之上做某事，那么采用1或2会是更好的解决方案?

From what I can see, if I don't require any implementation logic in the base, then an interface gives me the most flexibility (as I'm then not limiting myself with regards multiple inheritance etc.), but if I require the base to be able to do something on top of whatever the derived classes are doing, then going with either 1 or 2 would be the better solution?

感谢大家的投入-这个周末，无论是在本网站还是在其他地方，我都读了很多东西，我认为我现在已经了解了这些方法，但我只想在语言正确的方式(如果我走对头的话).希望我也已正确标记了此标记.

Thanks for any input on this guys - I have read so much this weekend, both on this site and elsewhere, and I think I understand the approaches now, yet I just want to clarify in a language specific way if I'm on the right track. Hopefully also I've tagged this correctly.

干杯， 特里

推荐答案

接口提供了最多的抽象；您不受任何特定实现的约束(如果实现因其他原因必须具有不同的基类，则很有用).

An interface offers the most abstraction; you aren't tied to any specific implementation (useful if the implementation must, for other reasons, have a different base class).

对于真正的多态性，virtual是必须的；多态性最常与类型子类关联...

For true polymorphism, virtual is a must; polymorphism is most commonly associated with type subclassing...

您当然可以混合两者:

public interface IFoo {
    void Bar();
}
class Foo : IFoo {
    public virtual void Bar() {...}
}
class Foo2 : Foo {
    public override ...
} 

abstract是另一回事； abstract的选择确实是:基类是否可以明智地定义它?如果没有默认实现，则必须为abstract.

abstract is a separate matter; the choice of abstract is really: can it be sensibly defined by the base-class? If there is there no default implementation, it must be abstract.

当有许多常见的实现细节时，一个通用的基类可能会有用，并且仅通过接口进行复制将毫无意义；但有趣的是-如果实现在每个实现中都不会改变，则扩展方法提供了一种将其公开在interface上的有用方法(这样，每个实现都不必这样做):

A common base-class can be useful when there is a lot of implementation details that are common, and it would be pointless to duplicate purely by interface; but interestingly - if the implementation will never vary per implementation, extension methods provide a useful way of exposing this on an interface (so that each implementation doesn't have to do it):

public interface IFoo {
    void Bar();
}
public static class FooExtensions {
    // just a silly example...
    public static bool TryBar(this IFoo foo) {
        try {
             foo.Bar();
             return true;
        } catch {
             return false;
        }
    }
}

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