迭代器：迭代集合中的每一项，无需关心集合中的内容。
实现迭代器的传统方式是使用迭代器模式，迭代器模式的示意图如下：
具体代码如下：
class Person
{
public string Name { get; set; }
public int Age { get; set; }
public Person(string name, int age)
{
this.Name = name;
this.Age = age;
}
}
class People:IEnumerable
{
public Person[] pvalue;
public People(Person[] p)
{
pvalue = p;
}
public IEnumerator GetEnumerator()
{
return new PeopleEnumerator(this);
}
}
class PeopleEnumerator:IEnumerator
{
Person[] pvalue;
int position;
public PeopleEnumerator(People p)
{
this.pvalue = p.pvalue;
position = -1;
}
public bool MoveNext()
{
if (position >= -1 && position < pvalue.Length)
{
position++;
}
return position < pvalue.Length;
}
public object Current
{
get
{
if (position >= 0 && position < pvalue.Length)
{
return pvalue[position];
}
else
{
return null;
}
}
}
public void Reset()
{
position = -1;
}
}
class Program
{
static void Main(string[] args)
{
Person[] PClassOne = new Person[4];
PClassOne[0] = new Person("夏利", 22);
PClassOne[1] = new Person("大众", 25);
PClassOne[2] = new Person("华为", 23);
PClassOne[3] = new Person("中兴", 24);
Console.WriteLine("传统的迭代器模式");
People Ppeople = new People(PClassOne);
IEnumerator PE = Ppeople.GetEnumerator();
while (PE.MoveNext())
{
Person p = (Person)PE.Current;
Console.WriteLine("我的名字叫{0},我的年龄为{1}", p.Name, p.Age);
}
Console.ReadKey();
}
}
输出为：
.net 可以使用yield 的方式简化迭代器的使用，将People改成如下的形式
class People:IEnumerable
{
public Person[] pvalue;
public People(Person[] p)
{
pvalue = p;
}
public IEnumerator GetEnumerator()
{
for (int i = 0; i < pvalue.Length; i++)
{
yield return pvalue[i];
}
}
}
无需在手动写IEnumerator，即可行程一个有效的迭代器。
转载于:https://www.cnblogs.com/Celvin-Xu/p/3434285.html