里氏替换原则

基本概念

任何父类出现的地方，子类都可以替代

语法表现：父类容器装子类对象，因为子类对象包含了父类所有的内容

方便进行对象存储和管理

---

class GameObject
{

}
class Player : GameObject
{
    public void PlayerAtk()
    {
        Console.WriteLine("玩家攻击")
    }
}
class Monster : GameObject
{
    public void MonsterAtk()
    {
        Console.WriteLine("怪物攻击")
    }
}
class Boss : GameObject
{
    public void BossAtk()
    {
        Console.WriteLine("首领攻击")
    }
}
//里氏替换原则，用父类容器装载子类对象
GameObject player = new Player();
GameObject monster = new Monster();
GameObject boss = new Boss();
GameObject [] objects = new GameObject[]{new Player(),new Monster(),new Boss()};
if(player is Player)
{
    //(player as Player).PlayerAtk();
    Player p = player as Player;
    p.PlayerAtk();
}
for (int i =0 ;i < objects.Length;i++)
{
    if(objects[i] is Player)
    {
        (objects[i] as Player).PlayerAtk();
    }
}

---

is :判断一个对象是否为指定类对象

返回值：bool 是就为真，不是就为假

as ：将一个对象转换为指定类对象

成功则返回指定类对象，失败返回 null