求释疑

Question

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;namespace IndexText
{
    public class Photo
    {
        string title;
        public Photo(string title)
        {
            this.title = title;
        }
        public string Title
        {
            get
            {
                return this.title;
            }
        }
    }
    class Album
    {
        Photo[] photos;
        public Album(int num)
        {
            photos = new Photo[num];
        }
        public Photo this[int index]
        {
            get
            {
                return photos[index];
            }
            set
            {
                photos[index] = value;
            }
        }
        public Photo this[string title]
        {
            get
            {                for(int i=0;i<photos.Length;i++)
                {
                    if (photos[i].Title == title)
                    {
                        return photos[i];
                    }
                }
                Console.WriteLine("没有找到");
            }
        }
    }
    class Test
    {
        static void Main(string[] args)
        {
            Photo julia = new Photo("julia");
            Photo  = new Photo("");
            Album friends = new Album(20);
            friends[0] = julia;
            friends[1] = ;
            Photo obj = friends[1];
            Console.WriteLine(obj.Title);
            obj = friends["julia"];
            Console.WriteLine(obj.Title);
            Console.ReadLine();
        }
    }
}
这个get编译出错，能不能帮个忙给解答个，为什么编译时错误提示为：错误 “IndexText.Album.this[string].get”: 并非所有的代码路径都返回值

Answer 1

已经说的很清楚了：“并非所有的代码路径都返回值”get
{
    for(int i=0;i<photos.Length;i++)
    {
        if (photos[i].Title == title)
        {
            return photos[i];
        }
    }
    Console.WriteLine("没有找到");    // 没有找到的话返回什么呢？？？
}

Answer 2

 Console.WriteLine("没有找到");
return null;