Ienumerable Ienumerator 進行迭代

一直都沒有深入的去接觸過Ienumerable 和Ienuerator 接口，而Ienumerable 裏面又有一個方法叫GetEnumerator方法。聽這些詞聽得頭都暈了。只知道他們的作用就是用來迭代。foreach提供支持。真正的去用還是沒有接觸過的。直接上一個微軟的例子好了。

 

using System; using System.Collections; public class Person { public Person(string fName,stringlName) { this.firstName = fName; this.lastName = lName; } private string firstName; private string lastName; } public class People:IEnumerable { private Person[] _people; public People(Person[] pArray) { _people = new Person[pArray.Length]; for(int i=0;i<pArray.Length;i++) { _people[i] = pArray[i]; } } public IEnumerator GetEnumerator() { return new PeopleEnum(_people); } } public class PeopleEnum:IEnumerator { public Person[] _people; int position = -1; public PeopleEnum(Person[] list) { _people = list; } public bool MoveNext() { position++; return (position<_people.Length); } public void Reset() { position = -1; } public object Current { get { try { return _people[position]; } catch(IndexOutOfRangeExcepction) { throw new InvalidOperationException(); } } } } //客戶端執行程序 class App { static void Main() { Person[] peopleArray = new Person[3] { new Person("John","Smith"), new Person("Jim","Johnson"); new Person("Sue","Rabon"); }; People peopleList = new People(peopleArray); foreach (People p in peopleList) Console.WriteLine(p.firstName+ "" +p.lastName); } } /* 程序運行結果: * * John Smith * Jim Johnson * Sue Rabon * */

PS:其實我還是不太清楚裏面的foreach是怎樣執行的，

要是哪位知道的能否在下面中帖寫出呢。