类继承

01.派生

using System;
using System.Collections.Generic;
using static System.Console;

namespace Inherit
{
    class Program
    {
        static void Main(string[] args)
        {
            //子类可以隐式转换父类
            Parent subclass=new Subclass();
            Parent parent = subclass;

            try
            {
                //父类不可以转换子类
                Parent newParent = new Parent();
                Subclass newSubclass = (Subclass)newParent;
                Console.WriteLine(newSubclass.age);
            }
            catch (Exception e)
            {
                WriteLine(e);
            }
               
            
           
            ReadKey();
        }
    }

    class Parent
    {
        public int hp { get; set; }
    }

    class Subclass:Parent
    {
        public int age { get; set; }
    }
}

02.继承

using System;
using System.Collections.Generic;
using static System.Console;

namespace Inherit
{
    class Program
    {
        static void Main(string[] args)
        {
            Contact contact=new Contact();
            contact.Name = "1";
            SubClass sub=new SubClass();
            sub.Name = "Sub";
            sub.Address = "192.168.01.01";
            ReadKey();
        }
    }

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

        public DateTime LastUpdate { get; set; }
    }

    class Contact:PdaItem
    {
        public string Address { get; set; }
        public string Phone { get; set; }
    }

    class SubClass:Contact
    {
        
    }

}

类型转换

class Program
    {
        static void Main(string[] args)
        {

            SubClass sub = new SubClass();
            sub.Name = "Sub";
            sub.Address = "192.168.01.01";

            PdaItem pdaItem = sub;//派生类sub 属于PdaItem类型  可以直接复制给PdaItem类型的变量 称为隐式转换
            Console.WriteLine(pdaItem.Name); // "Sub"

            PdaItem newPdaItem=new PdaItem();
            SubClass newSub = (SubClass) newPdaItem;   //显示转换
            Console.WriteLine(newSub.Phone); //Phone不属于newSub对象实例 转换失败
            ReadKey();
        }
    }

  

    class PdaItem:Object
    {
        public string Name { get; set; }

        public DateTime LastUpdate { get; set; }
    }

    class Contact:PdaItem
    {
        public string Address { get; set; }
        public string Phone { get; set; }
    }

    class SubClass:Contact
    {
        
    }

static void Main(string[] args)
        {

            SubClass sub = new SubClass();
            sub.Name = "Sub";
            sub.Address = "192.168.01.01";

            PdaItem pdaItem = sub;//派生类sub 属于PdaItem类型  可以直接复制给PdaItem类型的变量 称为隐式转换
            Console.WriteLine(pdaItem.Name); // "Sub"

            Console.WriteLine(sub.GetHashCode()); 
            Console.WriteLine(pdaItem.GetHashCode());
           
            ReadKey();
        }

03.重写

04.抽象类
05.System.Object
06.is操作符