里氏转换

里氏转换
子类可以赋值给父类
如果父类中装的是子类,可以将父类转换成子类
可以使用关键字as/is转换

    class Program
    {
        static void Main(string[] args)
        {
            //子类赋值给父类
            Person p = new Student();
            //父类中装的是子类,可以将父类转换成子类
            Student s = (Student)p;
            //使用as关键字转换 转换是被返回null
            Teacher t = p as Teacher;
            //使用关键字is转换
            if (p is Teacher)
            {
                Console.WriteLine("转换成功");
            }
            else
            {
                Console.WriteLine("转换失败");
            }

        }
    }

 public class Person
    {
        public string Name
        {
            get;
            set;
        }
    }

    public class Student : Person
    {
        public int ID
        {
            get;
            set;
        }
    }

    public class Teacher:Person
    {
        public double Salary
        {
            get;
            set;
        }
    }