ConcreteAggregate a = new ConcreteAggregate();a[0] = "A";a[1] = "B";a[2] = "C";a[3] = "D";Iterator i = new ConcreteIterator(a);object item = i.First();while (!i.IsDone()){Console.WriteLine("{0} 请买车票！ ", i.CurrentItem());i.Next();}Console.ReadLine();/// <summary>/// 迭代器（Iterator） 抽象类/// </summary>abstract class Iterator{public abstract object First();public abstract object Next();public abstract bool IsDone();public abstract object CurrentItem();} /// <summary>/// Aggregate 集聚抽象类/// </summary>abstract class Aggregate{public abstract Iterator CreateIterator();}/// <summary>/// ConcreteIterator 具体迭代器/// </summary>class ConcreteIterator : Iterator{//创建一个具体集聚类对象private ConcreteAggregate aggregate;private int current = 0;//初始化具体集聚类传入对象public ConcreteIterator(ConcreteAggregate aggregate){this.aggregate = aggregate;}public override object First(){return aggregate[0];} public override object Next(){object ret = null;current++;if (current < aggregate.Count)ret = aggregate[current];return ret;}public override bool IsDone(){return current >= aggregate.Count ? true : false;} public override object CurrentItem(){return aggregate[current];}}/// <summary>/// 具体 集聚类/// </summary>class ConcreteAggregate : Aggregate{private IList<object> items = new List<object>();public override Iterator CreateIterator(){return new ConcreteIterator(this);}public int Count{ get { return items.Count; } }//索引public object this[int index]{get { return items[index]; }set { items.Insert(index, value); }}  }

    public interface IEumerator{object Current{ get; }bool MoveNext();void Reset(); }public interface IEnumerable{IEumerator GetEnumerator();}