ublic class DaysoftheWeek:System.Collections.IEnemberable{
   string[] m_Days={"Sun","MOn","Tue","Wed","Thr","Fri","Sat"};
   public System.Collections.IEnumerator GetEnumerator()
   {
      for(int i=0;i<m_Days.Length;i++)
      {
          yield return m_Days[i];
      }   
   }
}
protected void Page_Load(object sender,Eventargs e)
{
   DaysofTheWeek week = new DaysofTheWeek();
   foreach(string day in week)
   {
       Response.Write(day+"");
   }
}红色标记的部分 删除后可以出结果,为什么添加上九不行呢?