继承如何对属性起作用?

How does inheritance work for Attributes?(继承如何对属性起作用?)

问题描述

属性上的 Inherited bool 属性指的是什么?

What does the Inherited bool property on attributes refers to?

这是否意味着如果我使用属性 AbcAtribute(具有 Inherited = true)定义我的类，并且如果我从该类继承另一个类，那么派生类也会应用相同的属性吗?

Does it mean that if I define my class with an attribute AbcAtribute (that has Inherited = true), and if I inherit another class from that class, that the derived class will also have that same attribute applied to it?

为了用一个代码示例来澄清这个问题，想象一下:

To clarify this question with a code example, imagine the following:

[AttributeUsage(AttributeTargets.Class, Inherited = true)]
public class Random: Attribute
{ /* attribute logic here */ }

[Random]
class Mother 
{ }

class Child : Mother 
{ }

Child 是否也应用了 Random 属性?

Does Child also have the Random attribute applied to it?

推荐答案

当Inherited = true(默认)时，表示你创建的属性可以被该属性修饰的类的子类继承.

When Inherited = true (which is the default) it means that the attribute you are creating can be inherited by sub-classes of the class decorated by the attribute.

所以 - 如果您使用 [AttributeUsage (Inherited = true)] 创建 MyUberAttribute

So - if you create MyUberAttribute with [AttributeUsage (Inherited = true)]

[AttributeUsage (Inherited = True)]
MyUberAttribute : Attribute
{
   string _SpecialName;
   public string SpecialName
   { 
     get { return _SpecialName; }
     set { _SpecialName = value; }
   }
}

然后通过装饰超类来使用属性...

Then use the Attribute by decorating a super-class...

[MyUberAttribute(SpecialName = "Bob")]
class MySuperClass 
{
  public void DoInterestingStuf () { ... }
}

如果我们创建 MySuperClass 的子类，它将具有此属性...

If we create an sub-class of MySuperClass it will have this attribute...

class MySubClass : MySuperClass
{
   ...
}

然后实例化一个 MySubClass 的实例...

Then instantiate an instance of MySubClass...

MySubClass MySubClassInstance = new MySubClass();

然后测试一下是否有属性...

Then test to see if it has the attribute...

MySubClassInstance <--- 现在拥有 MyUberAttribute，其中Bob"作为 SpecialName 值.

MySubClassInstance <--- now has the MyUberAttribute with "Bob" as the SpecialName value.

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