C# 中实现 foreach 功能

选自http://www.cnblogs.com/anjou/archive/2007/07/05/807357.html

1. MySplit 类

     ///   <summary>      ///  MySplit 类      ///   </summary>      public   class  MySplit : IEnumerable     {          private   string [] elements;          public  MySplit( string  source,  char [] delimiters)         {             elements  =  source.Split(delimiters);         }         IEnumerator IEnumerable.GetEnumerator()         {              return   new  MyEnumerator( this );         }          #region  在嵌套类中实现 IEnumerator 接口          ///   <summary>          ///  在嵌套类中实现 IEnumerator 接口，以便以后方便创建多个枚举          ///   </summary>          public   class  MyEnumerator : IEnumerator         {              private   int  position  =   - 1 ;              private  MySplit t;              public  MyEnumerator(MySplit t)             {                  this .t  =  t;             }              public   bool  MoveNext()             {                  if  (position  <  t.elements.Length  -   1 )                 {                     position ++ ;                      return   true ;                 }                  else                 {                      return   false ;                 }             }              public   void  Reset()             {                 position  =   - 1 ;             }              object  IEnumerator.Current             {                  get                 {                      try                     {                          return  t.elements[position];                     }                      catch  (IndexOutOfRangeException)                     {                          throw   new  InvalidOperationException();                     }                 }             }         }          #endregion     }

2. 使用

    MySplit mySplit  =   new  MySplit( " 大豆男生: I Love You! " ,  new   char [] {  '   ' ,  ' - '  });      foreach  ( string  item  in  mySplit)     {         Console.WriteLine(item);     }

3. 输出结果    大豆男生:    I    Love    You!