foreach内部原理

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实现了IEnumerator接口和GetEnumerator()方法的类都可以进行foreach排序。

1，建一个Myclass类，实现IEnumerable接口，在该接口中有个GetEnumerator()方法，返回值类型为IEnumerato，在建一个辅佐类实现了IEnumerato接口

using System;

using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;

namespace _05_foreach
{
class Myclass :IEnumerable
{
/// <summary>
/// 枚举器
/// </summary>
public class MyClassEnum : IEnumerator
{
public Student[] students;
public MyClassEnum(Student[] students)
{
this.students = students;
}
private int position = -1;
public object Current
{
get { return students[position]; }
}

public bool MoveNext()
{
position++;
return position < students.Length;
}

public void Reset()
{
position = -1;
}
}

private Student[] _students;
public Myclass(Student[] stu)
{
this._students = stu;
}
public IEnumerator GetEnumerator()
{
return new MyClassEnum(_students);
}
}

}

--------------学生类---------------

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace _05_foreach
{
class Student
{
public Student(string name)
{
this.name = name;
}
private string name;

public string Name
{
get { return name; }
set { name = value; }
}
}
}

------------------------调用myclass类对student[] 进行排序

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace _05_foreach
{
class Program
{
static void Main(string[] args)
{
Student stu1 = new Student("张三");
Student stu2 = new Student("李四");
Student stu3 = new Student("王五");
Myclass my = new Myclass(new Student[] { stu1, stu2, stu3 });
foreach (Student item in my)
{
Console.WriteLine(item.Name);
}
Console.Read();
}
}
}