Class是否需要实现IEnumerable才能使用Foreach

using System;
using System.Collections;
using System.Collections.Generic;

public class MyClass : IEnumerable<int>
{
    private int[] _numbers = new int[] { 1, 2, 3, 4, 5 };

    public IEnumerator<int> GetEnumerator()
    {
        foreach (int number in _numbers)
        {
            yield return number;
        }
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }
}

public class Program
{
    public static void Main()
    {
        MyClass myClass = new MyClass();

        foreach (int number in myClass)
        {
            Console.WriteLine(number);
        }
    }
}