3.C#知识点：is和as

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace IsAndAsTest
{
    class Program
    {
        static void Main(string[] args)
        {
            object child = new Child();
            bool b1 = (child is Father);
            bool b2 = (child is Mother);
            Console.WriteLine(b1);//返回true
            Console.WriteLine(b2);//返回false
            Console.ReadKey();
        }
    }
    public class Father
    {

    }
    public class Child:Father
    {

    }
    public class Mother
    {

    }
}

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace IsAndAsTest
{
    class Program
    {
        static void Main(string[] args)
        {
            object child = new Child();
            //bool b1 = (child is Father);
            //bool b2 = (child is Mother);
            //Console.WriteLine(b1);//返回true
            //Console.WriteLine(b2);//返回false
            //Console.ReadKey();
            Father f1 = child as Father;//可以得到转换成功,得到对象
            Mother m1 = child as Mother;//转换失败,m1的值为null
        }
    }
    public class Father
    {

    }
    public class Child:Father
    {

    }
    public class Mother
    {

    }
}

            Father F2 = new Father();
            Child C1 = (Child)F2;