C#中的yield return用法演示源码

下边代码段是关于C#中的yield return用法演示的代码。
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;

class Program
{
public static IEnumerable<string> SimpleList() {
yield return "1";
yield return "2";
yield return "3";
}

public static void Main(string[] args) {
foreach (String item in SimpleList())
Console.WriteLine(item); }
}