C# 中is,As运算符号

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); } } }}