c#索引器

索引器定义：索引器是封装了一组值的智能数组，它让用户可以自定义访问类型并以数组的形式访问类中的数据。索引实际上是有参属性

using System;
using System.Collections.Generic;

namespace 编码练习
{
    public class Student : ICloneable
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public int Age { get; set; }
        public Student(int id, string name, int age)
        {
            this.Id = id;
            this.Name = name;
            this.Age = age;
        }
        public void ShowData()
        {
            Console.WriteLine("id:" + this.Id + "  name:" + this.Name + "  age:" + this.Age);
        }
        //克隆，复制的是数据不是引用
        public object Clone()
        {
            return (object)this.MemberwiseClone();
        }

    }
    public class StudentIndexer
    {
        private List<Student> Fstudents { get; set; }
        public StudentIndexer()
        {
            Fstudents = new List<Student>();
        }
        //按ID索引
        public Student this[int id]
        {
            get
            {
                foreach (var stu in Fstudents)
                {
                    if (stu.Id == id)
                    {
                        return (Student)stu.Clone();
                    }
                }
                return null;
            }
            set { Fstudents.Add(value); }
        }
        //按姓名索引
        public Student this[string name]
        {
            get
            {
                foreach (var stu in Fstudents)
                {
                    if (stu.Name == name)
                    {
                        return (Student)stu.Clone();
                    }
                }
                return null;
            }
            set { Fstudents.Add(value); }
        }
        //按姓名和id索引
        public int this[string name, int id]
        {
            get
            {
                foreach (var stu in Fstudents)
                {
                    if (stu.Name == name && stu.Id == id)
                    {
                        return stu.Age;
                    }
                }
                return 0;
            }
            set { Fstudents.Add(new Student(id, name, value)); }
        }
    }
    public class Start
    {
        private static StudentIndexer FstudentIndexer;
      
        public static void Main()
        {
            //往索引里面添加元素
            FstudentIndexer = new StudentIndexer();
            FstudentIndexer[11] = new Student(11, "李四", 23);
            FstudentIndexer["李四"] = new Student(12, "李四", 23);
            FstudentIndexer["王五", 13] = 24;
            FstudentIndexer[11].ShowData();
            FstudentIndexer["王五"].ShowData();
            FstudentIndexer["李四"].ShowData();

        }
    }

}

附加知识点：

ICloneable接口的用法，该接口复制的是数据不是引用

  public object Clone()
        {
            return (object)this.MemberwiseClone();
        }