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）