new and override

时间:2022-05-07
本文章向大家介绍new and override,主要内容包括其使用实例、应用技巧、基本知识点总结和需要注意事项,具有一定的参考价值,需要的朋友可以参考一下。

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)