C＃覆盖公共成员，并使其私人 [英] C# override public member and make it private

问题描述

可能吗？你可以改变的任何访问的到的什么的东西？

Possible? Can you change the access of anything to anything else?

推荐答案

没有，你可以的隐藏在子类中的私有方法的公有成员，但你不能替换有私单子类中的公共成员。而且，实际上，它不只是一个公共/私人的事情，这也适用于缩小一般访问。

No, you can hide a public member with a private method in a subclass, but you cannot override a public member with a private one in a subclass. And, in actually, it's not just a public/private thing, this applies to narrowing the access in general.

修订：通过隐藏了更严格的访问 - 在这种情况下，私人的访问 - 你会的还是的看到从基类或子类的基类成员引用，但它会推迟到提供新的访问级别时，新的方法。

Revised: By hiding with a more restrictive access - in this case private access - you will still see the base class member from a base-class or sub-class reference, but it would defer to the new method when available from the new access level.

因此​​，在一般情况下，当你躲，躲花费precedence时，在其访问级别可见。否则原来的方法是使用所述一个

So in general, when you hide, the hide takes precedence when visible at its access level. Otherwise the original method is the one used.

public class BaseClass
{
    public virtual void A() { }

    public virtual void B() { }
}

public class SubClass
{
    // COMPILER ERROR, can't override to be more restrictive access
    private override void A() { }

    // LEGAL, you can HIDE the base class method, but which is chosen 
    // depends on level accessed from
    private new void B() { }
}

所以 SubClass.B（）隐藏的仅仅是基类的方法时，它可以访问。也就是说，如果你调用 SubClass.B（） 子类的内部那么它将<$的隐藏表单C $ C> B（），但因为 B（）是私有的，它是不可见的自身之外的类，因此他们仍然看到 BaseClass.B（）。

So SubClass.B() ONLY hides the base class methods when it is accessible. That is, if you call SubClass.B() inside of SubClass then it will take the hidden form of B(), but since B() is private, it is not visible to classes outside of itself, and thus they STILL see BaseClass.B().

长和短的是：

1）不能覆盖的方法以增加限制（接入明智的）。 2）可以隐藏与更具限制性一种方法，但它只会产生作用，其中该新的接入类型是可见的，否则一个都代表着所述基

1) You cannot override a method to be more restrictive (access wise). 2) You can hide a method with a more restrictive one, but it will only have an effect where that new access type is visible, otherwise the base one stands.

public class BaseClass
{
    public virtual void A() { }
    public virtual void B() { }
}

public class SubClass : BaseClass
{
    public virtual void A() { B(); }

    // legal, you can do this and B() is now hidden internally in SubClass,
    // but to outside world BaseClass's B() is still the one used.
    private new void B() { }
}

// ...

SubClass sc = new SubClass();
BaseClass bc = new BaseClass();

// both of these call BaseClass.B() because we are outside of class and can't
// see the hide SubClass.B().
sc.B();
bc.B();

// this calls SubClass.A(), which WILL call SubClass.B() because the hide
// SubClass.B() is visible within SubClass, and thus the hide hides BaseClass.B()
// for any calls inside of SubClass.
sc.A();

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