从"base.base“类调用方法？

Question

“假定以下代码：

public class MultiplasHerancas
{
    static GrandFather grandFather = new GrandFather();
    static Father father = new Father();
    static Child child = new Child();

    public static void Test() 
    {
        grandFather.WhoAreYou();
        father.WhoAreYou();
        child.WhoAreYou();

        GrandFather anotherGrandFather = (GrandFather)child;
        anotherGrandFather.WhoAreYou(); // Writes "I am a child"
    }

}

public class GrandFather
{
    public virtual void WhoAreYou() 
    {
        Console.WriteLine("I am a GrandFather");
    }
}

public class Father: GrandFather
{
    public override void WhoAreYou()
    {
        Console.WriteLine("I am a Father");
    }
}

public class Child : Father 
{
    public override void WhoAreYou()
    {
        Console.WriteLine("I am a Child");

    }
}

我想打印“我是一个祖父”从“孩子”对象。

如何在"base.base“类上执行子对象？我知道我可以执行基本方法(它会打印“我是一个父亲”)，但我想打印“我是一个GrandFather"！如果有这样的方法，在OOP设计中推荐吗？

注:我不使用/将使用这种方法，我只是想加强知识继承。

Answer 1

这只能使用Method Hiding -

public class GrandFather
{
    public virtual void WhoAreYou()
    {
        Console.WriteLine("I am a GrandFather");
    }
}

public class Father : GrandFather
{
    public new void WhoAreYou()
    {
        Console.WriteLine("I am a Father");
    }
}

public class Child : Father
{
    public new void WhoAreYou()
    {
        Console.WriteLine("I am a Child");            
    }
}

就这样叫它-

Child child = new Child();
((GrandFather)child).WhoAreYou();

使用new关键字hides the inherited member of base class in derived class。

Answer 2

尝试使用“新”关键字而不是“覆盖”，并从方法中删除“虚拟”关键字；)

Answer 3

这个程序在你运行时会出错。确保子对象将引用父类，然后使用引用类型转换调用方法Ex: child =new祖父()；/这里我们正在创建引用父类的子实例。/((祖父)子).WhoAreYou()；/*现在我们可以使用引用类型*/，否则它们在祖父类型转换下会出现错误。