C# 继承、重载、多态

写个测试，一看便知

父类：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Component
{
    public virtual void Test()
    {
        UnityEngine.Debug.Log("this is parent component");
    }
}

子类

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class SubComponent : Component
{
    public override void Test()
    {
        UnityEngine.Debug.Log("this is sub component");
    }
}

调用结果：

//Component com = new SubComponent();
//com.Test();//print：this is sub component

//Component com = new Component();
//com.Test();//print：this is parent component

//Component com = new SubComponent();
//(com as SubComponent).Test();//print：this is sub component

//Component com = new Component();
//(com as SubComponent).Test();//报错，print：NullReferenceException