扩：new and override

昨天有个网友问我继承里面的new和override关键词有啥区别，呃，我们来看个例子就知道了

new ==》隐藏父类同名方法  override==》覆盖

定义一个父类：

    public class People
    {
        /// <summary>
        ///ushort参考： https://msdn.microsoft.com/zh-CN/library/cbf1574z.aspx
        /// </summary>
        public string Name { get; set; }
        public ushort Age { get; set; }

        public People(string name, ushort age)
        {
            this.Name = name;
            this.Age = age;
        }
        public void Hi()//People
        {
            Console.WriteLine("Name: " + this.Name + " Age: " + this.Age);
        }
        public virtual void Show()//People
        {
            Console.WriteLine("Name: " + this.Name + " Age: " + this.Age);
        }
    }

　　定义一个子类:

    public class Student : People
    {
        #region 属性
        /// <summary>
        /// 学校
        /// </summary>
        public string School { get; set; }
        /// <summary>
        /// 班级
        /// </summary>
        public string StrClass { get; set; }
        /// <summary>
        /// 学号
        /// </summary>
        public string StrNum { get; set; }
        #endregion

        #region 构造函数
        /// <summary>
        /// 调用父类构造函数
        /// </summary>
        /// <param name="name"></param>
        /// <param name="age"></param>
        public Student(string name, ushort age) : base(name, age)
        {

        }
        public Student(string name, ushort age, string school, string strClass, string strNum) : this(name, age)
        {
            this.School = school;
            this.StrClass = strClass;
            this.StrNum = strNum;
        } 
        #endregion

        /// <summary>
        /// new-隐藏
        /// </summary>
        public new void Hi()//Student
        {
            Console.WriteLine("Name: " + this.Name + " Age: " + this.Age + " School: " + this.School + " strClass: " + this.StrClass + " strNum: " + this.StrNum);
        }
        /// <summary>
        /// override-覆盖
        /// </summary>
        public override void Show()//Student
        {
            Console.WriteLine("Name: " + this.Name + " Age: " + this.Age + " School: " + this.School + " strClass: " + this.StrClass + " strNum: " + this.StrNum);
        }
    }

　　调用一下

static void Main(string[] args)
        {
            People p = new Student("app", 10, "北京大学", "001", "01001");
            p.Hi(); p.Show();

            System.Console.WriteLine();

            Student s = p as Student;
            s.Hi(); s.Show();

            System.Console.ReadKey();
        }

　　输出：

可以发现，用new修饰的方法，其父方法并没有被改变，只是被隐藏了

用override重写的方法却被覆盖，从而改变了（多态）