步步为营-06-索引器

索引器-经常用,但不常写,仅作为知识点了解一下

1:定义Person类,类中定义一个数组字段

2:为了方便外部访问,封装为属性

  int[] numbers = new int[5];

　 public int[] Numbers         {       

      get { return numbers; }            

　　 set { numbers = value; }       

  }

3:外部访问

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Indexer
{
    class Program
    {
        static void Main(string[] args)
        {
            Person p = new Person();
            p.Numbers = new int[] {1,2,2,3,8,5};
            foreach (var item in p.Numbers)
            {
                Console.WriteLine(item);
            }
            Console.Read();
        }
    }
}

现在想不通过属性直接索引器访问.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Indexer
{
    class Program
    {
        static void Main(string[] args)
        {
            Person p = new Person();
            //p.Numbers = new int[] {1,2,2,3,8,5};
            //foreach (var item in p.Numbers)
            //{
            //    Console.WriteLine(item);
            //}
            p[0] = 1;
            p[4] = 5;
            for (int i = 0; i < 5; i++)
            {
                Console.WriteLine(p[i]);
            }
            Console.Read();
        }
    }
}

4:进一步介绍索引器的重载,通过字典

 Dictionary< string,int> dic = new Dictionary< string,int>();
        public  int this[string index]
        {
            set { dic[index] = value; }
            get { return dic[index]; }
        }

在main方法中调用

 p["张三"] = 1;
Console.WriteLine(p["张三"]);