interface Iterator
{
object First();
object Next();
bool isDone();
object CurrentItem();
}
class myIterator : Iterator
{
private MyAggragate items;
private int cuttent = 0;
public myIterator(MyAggragate _items)
{
items = _items;
}
public object CurrentItem()
{
return items[cuttent];
}
public object First()
{
return items[0];
}
public bool isDone()
{
return cuttent>=items.Count?true:false;
}
public object Next()
{
cuttent++;
if (cuttent >= items.Count)
return null;
return items[cuttent];
}
}
abstract class Aggragate
{
public abstract Iterator CreateIterator();
}
class MyAggragate : Aggragate
{
private IList<string> list = new List<string>();
public int Count
{
get
{
return list.Count;
}
}
public string this[int index]
{
get
{
return list[index];
}
set
{
list.Insert(index, value);
}
}
public override Iterator CreateIterator()
{
return new myIterator(this);
}
}
//前端
static void Main(string[] args)
{
MyAggragate a = new MyAggragate();
a[0] = "张三";
a[1] = "李四";
a[2] = "王五";
a[3] = "王五2";
diedaiqi.Iterator i = new myIterator(a);
var item = i.First();
Console.WriteLine("{0}1", item);
while (!i.isDone())
{
Console.WriteLine("{0}",i.CurrentItem());
i.Next();
}
Console.ReadLine();
}
总结：访问聚集对象，不管该对象是什么，需要遍历的时候，就使用迭代器。
迭代器模式：为聚集提供开始、下一个、是否结束、当前处于哪一项的统一的接口。
C#的集合什么的已经在内部实现了迭代器。
foreach(string item in a)
{
console.write("当前{0}",item);
}的内部实现其实是：
IEnumerator<string> e=a.GetEnumerator();
while(e.Next())
{
console.write("当前{0}",e.Current);
}
原文地址：http://blog.51cto.com/5591787/2118484
