Using yield to implement an IEnumerator

using System;
using System.Collections;
public class MyCollection : IEnumerable
{
    int[] data = { 1, 2, 3 };

    public IEnumerator GetEnumerator()
    {
        foreach (int i in data)
            yield return i;
    }
}

class Sample
{
    public static void Main()
    {
        foreach (int i in new MyCollection())
            Console.WriteLine(i);

    }
}