IEnumerable IEnumerator 分类： .NET 2014-05-13 17:38 350人阅读 评论(0) 收藏

看了官方的、网上其他的，写了2个demo，只不过还是没发现哪里会用到。

IEnumerable和IEnumerator都是System.Collections下的接口，结构分别如下：

namespace System.Collections
{
    public interface IEnumerable
    {
        IEnumerator GetEnumerator();
    }
}

namespace System.Collections
{
    // Summary:
    //     Supports a simple iteration over a nongeneric collection.
    [ComVisible(true)]
    [Guid("496B0ABF-CDEE-11d3-88E8-00902754C43A")]
    public interface IEnumerator
    {
        // Summary:
        //     Gets the current element in the collection.
        //
        // Returns:
        //     The current element in the collection.
        //
        // Exceptions:
        //   System.InvalidOperationException:
        //     The enumerator is positioned before the first element of the collection or
        //     after the last element.
        object Current { get; }

        // Summary:
        //     Advances the enumerator to the next element of the collection.
        //
        // Returns:
        //     true if the enumerator was successfully advanced to the next element; false
        //     if the enumerator has passed the end of the collection.
        //
        // Exceptions:
        //   System.InvalidOperationException:
        //     The collection was modified after the enumerator was created.
        bool MoveNext();
        //
        // Summary:
        //     Sets the enumerator to its initial position, which is before the first element
        //     in the collection.
        //
        // Exceptions:
        //   System.InvalidOperationException:
        //     The collection was modified after the enumerator was created.
        void Reset();
    }
}

Demo1：

class Program
{
    static void Main(string[] args)
    {
        Book[] books = new Book[3] { new Book() { BookName = "java" }, new Book() { BookName = ".net" }, new Book() { BookName = "php" } };

        BookShop bookShop = new BookShop(books);

        //输出java .net php
        foreach (Book book in bookShop)
        {
            Console.WriteLine(book.BookName);
        }
        Console.Read();
    }
}

//此类没有实现IEnumerable，只实现GetEnumerator()方法即可，因为数组本身已经有鸟~
public class BookShop
{
    public Book[] books = new Book[4];

    public BookShop(Book[] books)
    {
        this.books = books;
    }

    public IEnumerator GetEnumerator()
    {
        return books.GetEnumerator();
    }
}

public class Book
{
    public string BookName { get; set; }
}

Demo2：

class Program
{
    static void Main(string[] args)
    {
        StringArray strArray = new StringArray("java,.net,php");

        //输出java .net php
        foreach (string s in strArray)
        {
            Console.WriteLine(s);
        }

        Console.Read();
    }
}

public class StringArray
{
    public string[] strArray;

    public StringArray(string str)
    {
        strArray = str.Split(',');
    }

    public IEnumerator GetEnumerator()
    {
        return new StringArrayEnumerator(strArray);
    }
}

public class StringArrayEnumerator : IEnumerator
{
    int position = -1;
    string[] strArray;

    public StringArrayEnumerator(string[] strArray)
    {
        this.strArray = strArray;
    }

    public bool MoveNext()
    {
        if (position < this.strArray.Length - 1)
        {
            position++;
            return true;
        }
        else
        {
            return false;
        }
    }

    public object Current
    {
        get { return strArray.ElementAt(position); }
    }

    public void Reset()
    {
        this.position = -1;//回到初始值
    }
}

版权声明：本文为博主原创文章，未经博主允许不得转载。