IEnumerable接口與IEnumerator接口

通過一個例子來看

-------------------------------------------------------Student.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Collections;
namespace ConsoleApplication6
{
    public class Student:IEnumerable
    {
        //數組
        public string[] s;
        //索引器
        public int i;
        public Student(string[] str)//構造函數，初始化數組
        {
            s = str;
        }
        public IEnumerator GetEnumerator()//迭代器
        {
            return s.GetEnumerator();
        }
    }
}

-------------------------------------------------------StiAll.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Collections;
namespace ConsoleApplication6
{
    public class StiAll:IEnumerator
    {
        //student對象
        Student s;
        //游標
        int i = -1;
        public StiAll(Student ss)//構造函數，初始化student對象
        {
            this.s = ss;
        }
 
        public object Current//獲取當前的項（只讀屬性）
        {
            get { return s.s[i]; }
        }
        public bool MoveNext()//將游標的位置向前移動
        {
            if (i<s.s.Length-1)//如果在s數組的長度范圍之內就返回true
            {
                i++;
                return true;
            }
            else
            {
                return false;
            }
        }
        public void Reset()//初始化游標
        {
            i = -1;
        }
    }
}

-------------------------------------------------------主程序

 Student s = new Student(new string[] { "呂蒙", "周泰", "黃蓋" });//實例化Student對象
            //第一種方式遍歷
            foreach (var item in s)
            {
                Console.WriteLine(item);//輸出呂蒙，周泰，黃蓋
            }
            //第二種方式遍歷
            StiAll sa = new StiAll(s);
            while (sa.MoveNext())
            {
                Console.WriteLine(sa.Current);//輸出呂蒙，周泰，黃蓋
            }
            Console.ReadKey();