类索引器

将实例对象中的不同字段分别映射到不同的下标，通过类似数组的方式访问对象，和属性一样可以get/set

using System;

namespace Hello
{
    class Shape
    {
        private int _width;
        private int _height;

        public int this[int index]
        {
            set
            {
                // 指定下标对应的字段
                switch (index)
                {
                    case 0:
                        this._width = value;
                        break;
                    case 1:
                        this._height = value;
                        break;
                }
            }
            get
            {
                switch (index)
                {
                    case 0:
                        return this._width;
                    case 1:
                        return this._height;
                    default:
                        throw new IndexOutOfRangeException("不存在该下标对应的字段");
                }
            }
        }

    }
    public class Program
    {
        public static void Main()
        {
            Shape shape = new Shape();
            // 此时shape中的字段分别对应不同的下标，超出则会报错
            shape[0] = 12;
            shape[1] = 20;
            Console.WriteLine("width = {0}, height = {1}", shape[0], shape[1]);
        }
    }
}

原文地址：https://www.cnblogs.com/esrevinud/p/12014094.html