在方法签名中使用新关键字通常只是为了可读性？ [英] Is using new keyword in method signature generally just for readability?

问题描述

我已阅读新关键字在方法签名，并已看到下面的示例这帖子，但我还是不明白为什么写 new 关键字在方法签名中。如果我们忽略它，它仍然会做同样的事情。它会编译。

I've read about new keyword in method signature and have seen the example below on this post, but I still don't get why to write new keyword in method signature. If we'll omit it, it still will do the same things. It will compile. There is gonna be a warning, but it will compile.

因此，在方法签名中写入 new 只是为了可读性？

So, writing new in method signature is just for readability?

public class A
{
   public virtual void One() { /* ... */ }
   public void Two() { /* ... */ }
}

public class B : A
{
   public override void One() { /* ... */ }
   public new void Two() { /* ... */ }
}

B b = new B();
A a = b as A;

a.One(); // Calls implementation in B
a.Two(); // Calls implementation in A
b.One(); // Calls implementation in B
b.Two(); // Calls implementation in B

推荐答案

为什么隐藏基类成员时不需要 new 关键字？原因是脆弱的基类问题。假设你有一个库：

Implicit in this question: why isn't the new keyword required when hiding a base class member? The reason is the brittle base class problem. Suppose you have a library:

public class Base
{
    public void M() { }
}

您已经在自己的代码库中派生了一个类：

and you've derived a class in your own code base:

public class Derived : Base
{
    public void N() { }
}

现在，库作者发布了一个新版本，向 Base ：

Now, the library authors release a new version, adding another method to Base:

public class Base
{
    public void M() { }
    public void N() { }
}

隐藏，你的代码现在无法编译！将新关键字设为可选意味着您现在所拥有的是一个新的警告。

If the new keyword were required for method hiding, your code now fails to compile! Making the new keyword optional means that all you now have is a new warning to worry about.

EDIT

正如Eric Lippert在他的评论中指出的，新警告担心大大低估了警告的目的，即挥动大红旗。当我写信的时候，我一定很匆忙;

As Eric Lippert points out in his comment, "new warning to worry about" drastically understates the purpose of the warning, which is to "wave a big red flag." I must have been in a hurry when I wrote that; it's annoying when people reflexively view warnings as annoyances to be tolerated rather than treating them as useful information.

EDIT 2

我终于找到了这个答案的源代码，当然，这是Eric的帖子之一： http ：//stackoverflow.com/a/8231523/385844

I finally found my source for this answer, which, of course, is one of Eric's posts: http://stackoverflow.com/a/8231523/385844

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