//************************************************************  
//  
// foreach应用示例代码  
//  
// Author：三五月儿  
//   
// Date：2014/09/10  
//  
//  
//************************************************************  
using System;
using System.Collections;
using System.Collections.Generic;
namespace IEnumerableExp
{
  class Program
  {
    static void Main(string[] args)
    {
      List<Student> studentList = new List<Student>() 
      {
        new Student(){Id = 1, Name = "三五月儿", Age = 23},
        new Student(){Id = 2, Name = "张三丰", Age = 108},
        new Student(){Id = 3, Name = "艾尔克森", Age = 25},
        new Student(){Id = 3, Name = "穆里奇", Age = 27}
      };
      foreach (var student in studentList)
      {
        Console.WriteLine("Id = {0}, Name = {1}, Age = {2}", student.Id,student.Name,student.Age);
      }
    }
  }
  public class Student
  {
    public int Id { get; set; }
    public string Name { get; set; }
    public int Age { get; set; }
  }
}

IL_00c6: callvirt  instance valuetype [mscorlib]System.Collections.Generic.List`1/Enumerator<!0> class [mscorlib]System.Collections.Generic.List`1<class IEnumerableExp.Student>::GetEnumerator() 
IL_00d1: call  instance !0 valuetype [mscorlib]System.Collections.Generic.List`1/Enumerator<class IEnumerableExp.Student>::get_Current()
IL_0102: call  instance bool valuetype [mscorlib]System.Collections.Generic.List`1/Enumerator<class IEnumerableExp.Student>::MoveNext()

IEnumerator<Student> studentEnumerator = studentList.GetEnumerator();
while (studentEnumerator.MoveNext())
{
   var currentStudent = studentEnumerator.Current as Student;
   Console.WriteLine("Id = {0}, Name = {1}, Age = {2}", currentStudent.Id, currentStudent.Name, currentStudent.Age);
}

//************************************************************  
//  
// foreach应用示例代码  
//  
// Author：三五月儿  
//   
// Date：2014/09/10  
//  
//  
//************************************************************  
using System;
using System.Collections;
using System.Collections.Generic;
namespace IEnumerableExp
{
  class Program
  {
    static void Main(string[] args)
    {
      Student[] students = new Student[4]
      {
        new Student(){Id = 1, Name = "三五月儿", Age = 23},
        new Student(){Id = 2, Name = "张三丰", Age = 108},
        new Student(){Id = 3, Name = "艾尔克森", Age = 25},
        new Student(){Id = 3, Name = "穆里奇", Age = 27}
      };
      StudentSet studentSet = new StudentSet(students);
      foreach (var student in studentSet)
      {
        Console.WriteLine("Id = {0}, Name = {1}, Age = {2}", student.Id, student.Name, student.Age);
      }
    }
  }
 
  public class Student
  {
    public int Id { get; set; }
    public string Name { get; set; }
    public int Age { get; set; }
  }
 
  public class StudentSet : IEnumerable
  {
    private Student[] students;
    public StudentSet(Student[] inputStudents)
    {
      students = new Student[inputStudents.Length];
      for (int i = 0; i < inputStudents.Length; i++)
      {
        students[i] = inputStudents[i];
      }
    }
 
    IEnumerator IEnumerable.GetEnumerator()
    {
      return (IEnumerator)GetEnumerator();
    }
 
    public StudentEnumerator GetEnumerator()
    {
      return new StudentEnumerator(students);
    }
  }
 
  public class StudentEnumerator : IEnumerator
  {
    public Student[] students;
    int position = -1;
    public StudentEnumerator(Student[] students)
    {
      this.students = students;
    }
 
    public bool MoveNext()
    {
      position++;
      return (position < students.Length);
    }
 
    public void Reset()
    {
      position = -1;
    }
 
    object IEnumerator.Current
    {
      get
      {
        return Current;
      }
    }
 
    public Student Current
    {
      get
      {
        try
        {
          return students[position];
        }
        catch (IndexOutOfRangeException)
        {
          throw new InvalidOperationException();
        }
      }
    }
  }
}