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:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | 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:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 | 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
1 2 3 4 5 6 7 8 9 10 11 12 | 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)
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