实现foreach遍历

【实现foreach遍历】

　　IEnumerable的原始版本存在于System.Collection中。

　　实现foreach遍历

　　一个类想要被foreach遍历，需要实现此IEnumerable接口。

 1 public class People : IEnumerable
 2 {
 3     private Person[] _people;
 4     public People(Person[] pArray)
 5     {
 6         _people = new Person[pArray.Length];
 7 
 8         for (int i = 0; i < pArray.Length; i++)
 9         {
10             _people[i] = pArray[i];
11         }
12     }
13 
14     IEnumerator IEnumerable.GetEnumerator()
15     {
16        return (IEnumerator) GetEnumerator();
17     }
18 
19     public PeopleEnum GetEnumerator()
20     {
21         return new PeopleEnum(_people);
22     }
23 }
24 
25 class App
26 {
27     static void Main()
28     {
29         Person[] peopleArray = new Person[3]
30         {
31             new Person("John", "Smith"),
32             new Person("Jim", "Johnson"),
33             new Person("Sue", "Rabon"),
34         };
35 
36         People peopleList = new People(peopleArray);
37         foreach (Person p in peopleList)
38             Console.WriteLine(p.firstName + " " + p.lastName);
39 
40     }
41 }

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