索引器的用法

using System;

namespace _03_21
{
    class Car
    {
        string[] wheels = new string[4];

        public Car()
        {
            wheels[0] = "左前轮";
            wheels[1] = "右前轮";
            wheels[2] = "左后轮";
            wheels[3] = "右后轮";
        }

        public string this [int index]    // Car类的索引器
        {
            get
            {
                return wheels[index];
            }
            set
            {
                wheels[index] = value;
            }
        }
    }

    class Class_03_21
    {
        public static void Main(String[] args)
        {
            Car car1 = new Car();

            Console.WriteLine("car1的第一个轮子是：{0}", car1[0]);
            Console.WriteLine("car1的第三个轮子是：{0}", car1[2]);

            car1[1] = "新的右前轮";
            car1[3] = "更新的右后轮";

            Console.WriteLine("car1的第二个轮子是：{0}", car1[1]);
            Console.WriteLine("car1的第四个轮子是：{0}", car1[3]);
        }
    }
}

using System;

namespace _03_22
{
    class Car
    {
        string[] wheels = new string[4];

        public Car()
        {
            wheels[0] = "左前轮";
            wheels[1] = "右前轮";
            wheels[2] = "左后轮";
            wheels[3] = "右后轮";
        }

        public string this [int index]    // Car类的索引器
        {
            get
            {
                return wheels[index];
            }
            set
            {
                wheels[index] = value;
            }
        }

        public int this [string wheel]
        {
            get
            {
                for(int i = 0; i < wheels.Length; ++i)
                {
                    if(wheels[i] == wheel) return i;
                }
                return -1;
            }
        }
    }

    class Class_03_22
    {
        public static void Main(String[] args)
        {
            Car car1 = new Car();

            Console.WriteLine("car1的右前轮是第{0}个轮子", car1["右前轮"]);
            Console.WriteLine("car1的左后轮是第{0}个轮子", car1["左后轮"]);
        }
    }
}