C#索引器

C#索引器关键实例代码

 

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Photo firstPhoto = new Photo("小轮");
            Photo secondPhoto = new Photo("小气");
            Ablum obj = new Ablum(2);
            obj[0] = firstPhoto;
            obj[1] = secondPhoto;
            Console.WriteLine(obj["小轮"].Title);
            Console.WriteLine(obj[1].Title);
        }
    }
    /// <summary>
    /// 照片类
    /// 字段title 照片标题，测试用
    /// </summary>
    class Photo
    {
        private string title;

        public string Title
        {
            get { return title; }
            set { title = value; }
        }

        public Photo()
        {
            this.Title = "默认名称";
        }

        public Photo(string title)
        {
            this.Title = title;
        }

    }

    class Ablum
    {
        public Photo[] photos;

        public Ablum()
        {
            photos = new Photo[2];
        }

        public Ablum(int length)
        {
            photos = new Photo[length];
        }
        /// <summary>
        /// 使用int类型的索引器
        /// </summary>
        /// <param name="index"></param>
        /// <returns></returns>
        public Photo this[int index]
        {
            get
            {
                if (index < 0 || index > photos.Length - 1)
                {
                    Console.Write("索引值无效");
                    return null;
                }
                return photos[index];
            }
            set
            {
                if (index < 0 || index > photos.Length - 1)
                {
                    Console.Write("索引值无效");
                    return;
                }
                photos[index] = value;
            }
        }
        /// <summary>
        /// 使用string类型的索引器
        /// </summary>
        /// <param name="index"></param>
        /// <returns></returns>
        public Photo this[string indexStr]
        {
            get
            {
                foreach (Photo objPhoto in photos)
                {
                    if (objPhoto.Title.Equals(indexStr))
                        return objPhoto;
                }
                Console.WriteLine("索引值错误");
                return null;
            }
            set
            {
                int count = 0;
                foreach (Photo objPhoto in photos)
                {
                    if (objPhoto.Title.Equals(indexStr))
                    {
                        photos[count] = value;
                    }
                    count++;
                    return;
                }
            }
        }
    }

}

 

输出结果：小轮

小气