C# IEnumerable和IEnumerator的区别，如何实现

我不是女神ヾ 2022-09-19 00:26 110阅读 0赞

IEnumerable接口和IEnumerator接口是.NET中非常重要的接口，二者有何区别？

1. 简单来说IEnumerable是一个声明式的接口，声明实现该接口的类就是“可迭代的enumerable”,但并没用说明如何实现迭代器(iterator).其代码实现为：

public interface IEnumerable  
         \{  
                IEnumerator GetEnumerator();  
          \}  
    2. 而IEnumerator接口是实现式接口，它声明实现该接口的类就可以作为一个迭代器iterator.其代码实现为：

public interface IEnumerator  
       \{  
                object Current \{ get; \}

bool MoveNext();  
                void Reset();  
        \}

3.一个collection要支持Foreach进行遍历，就必须实现IEnumerable,并一某种方式返回迭代器对象:IEnumerator.

那么又如何实现这两个接口呢？ 其代码如下：

假设有一个Person类，其有两个属性FirstName和LastName

public class Person  
    \{  
        public string FirstName \{ get; set; \}  
        public string LastName \{ get; set; \}  
        public Person(string firstName, string lastName)  
        \{  
            this.FirstName = firstName;  
            this.LastName = lastName;  
        \}  
    \}

另外通过People类来实现IEnumerable和IEnumerator接口.

//实现IEnumerable接口

public class People :IEnumerable

public Person \[\] pers;

public People(Person \[\] ps)

this.pers = ps;

public IEnumerator GetEnumerator()

//foreach(Person p in pers)

// \{

//  yield return p;

// \}

return new People1(pers);

//实现IEnumerator接口

public class People1 : IEnumerator  
    \{  
        public Person\[\] pers;  
        public People1(Person\[\] per)  
        \{  
            this.pers = per;  
        \}  
        int position = -1;

public bool MoveNext()  
        \{  
            position++;  
            return position < pers.Length;  
        \}  
        public void Reset()  
        \{  
            position=-1;  
        \}  
        public object Current  
        \{  
            get  
            \{  
               try  
               \{  
                   return pers\[position\];  
               \}  
                catch(IndexOutOfRangeException ex)  
                \{  
                    throw new InvalidOperationException();  
                \}  
            \}  
        \}  
    \}