实现接口的类的继承 [英] Inheritance of classes that implements interfaces

问题描述

大家好.

我有这段代码来说明我的问题:

Hello everybody.

I have this piece of code to explain my problem:

using System;
using System.Collections.Generic;
using System.Text;
namespace ConsoleApplication1
{
    public interface Interface1
    {
        void Test();
    }
    public class BaseClass : Interface1
    {
        public void Test()
        {
            throw new NotImplementedException(); //Execution jumps here always. I need it to execute this line only if Class1 doesn't have a Test function.
        }
    }
    public class Class1 : BaseClass
    {
        public void Test()
        {
            return; //Why not here?
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Class1 a = new Class1();
            Object obj = a as Object;
            Interface1 itf = a as Interface1;
            itf.Test(); // <-- Why it calls BaseClass.Test() ?
        }
    }
}

当程序执行到Main函数中的itf.Test()时，我希望它会调用Class1.Test()函数而不是BaseClass.Test().仅当未实现Class1.Test()函数时，才需要执行BaseClass.Test()方法.在这种情况下，程序将触发NotImplementedException.
有人可以帮我吗?谢谢.

When the program execution reaches the itf.Test() in the Main function I expect it would call the Class1.Test() function instead of the BaseClass.Test(). I need to execute the BaseClass.Test() method only if Class1.Test() function is not implemented. In that case the program would fire a NotImplementedException.
Anyone could help me please? Thanks.

推荐答案

按如下所示更改代码:

Change your code as follows:

public class BaseClass : Interface1
{
    public virtual void Test()
    {
        // some code here
    }
}

public class Class1 : BaseClass
{
    public override void Test()
    {
        // some other code here
    }
}

上一个答案是正确的.您使用virtual表示可以重写该方法.在子类中重写该方法时，可以使用重写.

非虚拟方法:
*无法覆盖
*比虚拟方法(早期绑定)要快

虚方法:
*可以覆盖
*比非虚拟方法要慢，因为绑定是在运行时(后期绑定).

Previous answer is correct. You use virtual to indicate that the method can be overriden. And you use override when you are re-writing that method in a child class.

non virtual method:
* it can''t be overriden
* it''s faster than virtual method (early binding)

virtual method:
* it can be overriden
* it''s slower than non virtual method because the binding is at runtime (late binding).

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