任何写“私人”的理由都可以。 C# 中的关键字？

发布于 2024-12-20 14:57:45 字数 506 浏览 1 评论 0原文

据我所知，private 是 C# 中默认的无处不在（这意味着如果我不写 public，protected< /code>、internal 等。默认情况下它将是 private）。（如果我错了，请纠正我。）

那么，编写该关键字的原因是什么，或者为什么它甚至为会员而存在？

例如，当自动生成事件处理程序时，它看起来像这样：

private void RatTrap_MouseEnter(object sender, CheeseEventArgs e)
{

}

但是如果这是隐含的和默认的，为什么它甚至会写为 private 呢？只是为了让新手开发人员（他们不知道这是 C# 默认值）知道它是私有的吗？或者编译器有什么区别？

此外，是否存在写入“private”（单独）会改变成员的可访问性的情况？

原文

As far as I know, private is the default everywhere in C# (meaning that if I don't write public, protected, internal, etc. it will be private by default). (Please correct me if I am wrong.)

So, what's the reason to write that keyword, or why does it even exist for members?

For example, when an event handler is auto-generated it looks like this:

private void RatTrap_MouseEnter(object sender, CheeseEventArgs e)
{

}

But why does it even write private if that's implied and default? Just so that novice developers (who don't know it's the C# default) know that it's private? Or is there a difference for the compiler?

Moreover, is there a case where writing "private" (alone) will change the accessibility of the member?

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傲鸠 2024-12-27 14:57:45

AFAIK，私有是 C# 中所有地方的默认值（这意味着如果我不写 public、protected、internal 等，默认情况下它将是私有的）。（如有错误请指正）

这不是真的。默认情况下，命名空间内定义的类型（类、结构、接口等）将是内部。此外，不同类型中的成员具有不同的默认可访问性（例如接口成员的公共）。有关详细信息，请参阅 MSDN 上的辅助功能级别。

还，

那么，编写该关键字的原因是什么，或者为什么它存在？

明确指定这一点有助于非常明确地表明您将该类型设为私有的意图。随着时间的推移，这有助于提高代码的可维护性。这可以帮助其他开发人员（或您自己）了解成员是默认私有的还是故意的等。

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说好的呢 2024-12-27 14:57:45

据我所知，私有是 C# 中所有地方的默认设置

不完全是 - 默认值是“此声明可用的最受限制的访问”。例如，对于顶级类型，默认值为 internal；对于嵌套类型，默认值为 private。

那么，编写该关键字的原因是什么，或者为什么它存在？

它使其明确，这有两个原因：

它使那些不知道默认值的人更清楚，根据你的问题（我个人从来不喜欢这个论点，但我认为值得一提）
它给出给人的印象是您有意决定将其设为私有，而不是仅仅采用默认值。

至于你的最后一部分：

此外，是否存在写入“private”（单独）会改变成员的可访问性的情况？

是的，为了让一半的财产比另一半更受限制：

// Public getter, public setter
public int Foo { get; set; }

// Public getter, private setter
public int Bar { get; private set; }

我曾经尽可能地采用默认值，但我已经确信（部分是由埃里克·利珀特（Eric Lippert）），明确表示你'我考虑过并决定将某些内容设为私有是个好主意。

就我个人而言，我希望有一种方法可以为密封/未密封的类型声明做到这一点 - 甚至可能没有默认值。我怀疑许多开发人员（包括我自己，如果我不小心的话）将类未密封只是因为这比密封它们更省力。

AFAIK, private is the default everywhere in C#

Not quite - the default is "the most restricted access available for this declaration". So for example, with a top-level type the default is internal; for a nested type the default is private.

So, what's the reason to write that keyword, or why does it even exist?

It makes it explicit, which is good for two reasons:

It makes it clearer for those who don't know the defaults, as per your question (I've never liked this argument, personally, but I figured it's worth mentioning)
It gives an impression that you've deliberately decided to make it private, rather than just gone with the defaults.

As for your last part:

Moreover is there a case where writing "private" (alone) will change the accessibility of the member?

Yes, for making half of a property more restrictive than the other:

// Public getter, public setter
public int Foo { get; set; }

// Public getter, private setter
public int Bar { get; private set; }

I used to go with defaults everywhere I could, but I've been convinced (partly by Eric Lippert) that making it clear that you've thought about it and decided to make something private is a good idea.

Personally I wish there were a way of doing that for sealed / unsealed, too, for type declarations - possibly not even have a default. I suspect that many developers (myself included if I'm not careful) leave classes unsealed just because it's less effort than making them sealed.

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纵山崖 2024-12-27 14:57:45

private 增加了视觉混乱。对于那些坚持认为它使事情变得明确的人，我想问：你在数学上也这样做吗？例如：

var answer = a + b / c;

如果 b / c 周围没有多余的括号，您是否会觉得不清楚？

C# 中的规则非常简单：默认情况下，所有内容都尽可能接近私有。因此，如果您需要比默认情况更加可见的内容，请添加一个修饰符。否则，不要在代码中添加不必要的关键字。

private adds visual clutter. To those who insist that it makes things explicit, I would ask: Do you do this with mathematics, too? For instance:

var answer = a + b / c;

Do you find that unclear without redundant parentheses around b / c?

The rule in C# is very simple: By default, everything is as close to private as it can be. So if you need something to be more visible than the default, add a modifier. Otherwise, don't add needless keywords to your code.

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