C#中is与As运算符号的使用详解

usingSystem;
usingSystem.Collections.Generic;
usingSystem.Text;
namespaceConsoleApplication1
{
   classIsOrAsClass
   {
       classAnimal
       {
           publicvoidEat()
           {
               Console.WriteLine("Eating...");
           }
           publicoverridestringToString()
           {
              return "IamEating";
           }
       }
       //家禽类
       classjia:Animal
       {

       }
       //狗
       classDog:jia
       {

       }
       //鸟
       classbird
       {

       }
       staticvoidMain()
       {
          IsOrAsClassapp=newIsOrAsClass();
          //
          Dogd=newDog();
          app.UseIsOpreate(d);
          app.UseAsOpreate(d);
          //
          birdb=newbird();
          app.UseAsOpreate(b);

       }
       //使用Is运算符
       voidUseIsOpreate(Animala)
       {
           if(aisjia)
           {
               jiaj=(jia)a;
               j.Eat();
           }
       }
       //使用AS运算符
       voidUseAsOpreate(objecto)
       {
           jiaj=oasjia;
           if(j!=null)
           {
               Console.WriteLine(j.ToString());
           }
           else
           {
               Console.WriteLine("{0}isnotAnimal",o.GetType().Name);
           }
       }
   }
}