C#索引器

来源：互联网发布：迪杰斯特拉算法简单编辑：程序博客网时间：2024/06/06 03:16

假设我们要定义一个类 Employee，它带有3个string型字段，那么可以使用字段的名称来访问它们。

如：

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace Learning{    class Employee    {        public string LastName;        public string FirstName;        public string CityOfBirth;    }    class Program    {               static void Main(string[] args)        {            Employee emp1 = new Employee();            emp1.LastName = "Doe";             emp1.FirstName = "Jane";            emp1.CityOfBirth = "Dallas";            Console.WriteLine("{0}", emp1.LastName);            Console.WriteLine("{0}", emp1.FirstName);            Console.WriteLine("{0}", emp1.CityOfBirth);                    }         }}

然而有的时候，使用索引访问它们会更加的方便。

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace Learning{    class Employee    {        public string LastName;        public string FirstName;        public string CityOfBirth;        public string this[int index]        {            set            {                switch (index)                {                    case 0: LastName = value;                        break;                    case 1: FirstName = value;                        break;                    case 2: CityOfBirth = value;                        break;                    default :                        throw new ArgumentOutOfRangeException("index");                }            }            get            {                switch (index)                {                    case 0: return LastName;                    case 1: return FirstName;                    case 2: return CityOfBirth;                    default :                        throw new ArgumentOutOfRangeException("index");                }            }        }    }    class Program    {               static void Main(string[] args)        {            Employee emp1 = new Employee();            emp1[0] = "Doe";            emp1[1] = "Jane";            emp1[2]= "Dallas";            Console.WriteLine("{0}", emp1[0]);            Console.WriteLine("{0}", emp1[1]);            Console.WriteLine("{0}", emp1[2]);                    }         }}

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