投射到接口是拳击转换吗? [英] Is casting to an interface a boxing conversion?

问题描述

我有一个接口IEntity

I have an interface IEntity

public interface IEntity{
    bool Validate();
}

我有一个实现此接口的Employee类

And I have a class Employee which implements this interface

public class Employee : IEntity{
    public bool Validate(){ return true; }
}

现在，如果我有以下代码

Now if I have the following code

Employee emp1 = new Employee();
IEntity ent1 = (IEntity)emp1; // Is this a boxing conversion?

如果不是拳击转换，那么演员阵容如何工作?

If it is not a boxing conversion then how does the cast work?

推荐答案

否，因为Employee是一个类，它是一个值类型.

No, since Employee is a class, which is a reference type rather than a value type.

来自 MSDN :

装箱是转换 值类型到类型对象或 由此实现的任何接口类型 值类型.当CLR框显示一个值时 类型，它将值包装在 System.Object并将其存储在 托管堆.拆箱提取 对象中的值类型.

Boxing is the process of converting a value type to the type object or to any interface type implemented by this value type. When the CLR boxes a value type, it wraps the value inside a System.Object and stores it on the managed heap. Unboxing extracts the value type from the object.

前面提到的MSDN链接提供了更多示例，这些示例应该有助于阐明该主题.

The aforementioned MSDN link has further examples that should help clarify the topic.

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