实现IEnumberable接口和IEnumberator

 class BookEnum : IEnumerator  //实现foreach语句内部,并派生
    {
 
        public Book[] _book; //实现数组
 
        int position = -;//设置“指针”
 
        public BookEnum(Book[] list)
        {
 
            _book = list; //实现list
 
        }
 
        public bool MoveNext()//实现向前移动
        {
 
            position++;     //位置增加
 
            return (position < _book.Length);   //返回布尔值
 
        }
 
        public void Reset()     //位置重置
        {
 
            position = -;
 
        }//重置指针为-1
 
        public object Current      //实现接口方法
        {
 
            get
            {
 
                try
                {
 
                    return _book[position];      //返回对象
 
                }
 
                catch (IndexOutOfRangeException)      //捕获异常
                {
 
                    throw new InvalidOperationException();     //抛出异常信息
 
                }
 
            }
 
        }
 
    }
 
    public class Book : IEnumerable
    {
 
        public string Name;
 
        public string Price;
 
        public Book(string name, string price)
        {
 
            Name = name;
 
            Price = price;
 
        }
 
        private Book[] book;
 
        public Book(Book[] array) //
        {
 
            book = array;
 
        }
 
        public IEnumerator GetEnumerator()    //实现接口
        {
 
            return new BookEnum(book);      //返回方法
        }
    }
 
public partial class MainWindow : Window
    {
        public Student stu;
        public MainWindow()
        {
            InitializeComponent();
            Book[] book = new Book[]
            {
 
                new Book("水浒",""),           
 
                new Book("三国",""),  
 
                new Book("西游","")
 
            };
 
            foreach (Book p in book)
            {
 
                this.textBox2.Text+="书的名字：" + p.Name + "；价格： " + p.Price;
 
            }
 
        }