如下所示：

复制代码 代码如下:

using System;

using System.Collections.Generic;

using System.Text;

namespace ConsoleApplication1

{

class IsOrAsClass

{

class Animal

{

public void Eat()

{

Console.WriteLine("Eating...");

}

public override string ToString()

{

return "I am Eating";

}

}

//家禽类

class jia:Animal

{

}

//狗

class Dog : jia

{

}

//鸟

class bird

{

}

static void Main()

{

IsOrAsClass app=new IsOrAsClass();

//

Dog d=new Dog();

app.UseIsOpreate(d);

app.UseAsOpreate(d);

//

bird b = new bird();

app.UseAsOpreate(b);

}

//使用Is运算符

void UseIsOpreate(Animal a)

{

if (a is jia)

{

jia j = (jia)a;

j.Eat();

}

}

//使用AS运算符

void UseAsOpreate(object o)

{

jia j = o as jia;

if (j != null)

{

Console.WriteLine(j.ToString());

}

else

{

Console.WriteLine("{0} is not Animal", o.GetType().Name);

}

}

}

}