public class Persons:IEnumerable

    {

        public Persons(string[] people)

        {

            this.people = people;

        }

        public string[] people { set; get; }

        public IEnumerator GetEnumerator()

        {

            return new PersonEnumable(people);

        }

    }

    public class PersonEnumable : IEnumerator

    {

        public PersonEnumable(string[] people)

        {

            this.people = people;

        }

        private string[] people { set; get; }

        private int index { set; get; } = -;

        /// <summary>

        /// 当前对象

        /// </summary>

        public object Current {

            get {

                if (index <  || index > people.Length-)

                    return null;

                else

                    return people[index];

            }

        }

        /// <summary>

        ///

        /// </summary>

        /// <returns></returns>

        public bool MoveNext()

        {

            if (index < people.Length-)

            {

                index++;

                return true;

            }

            return false;

        }

        /// <summary>

        ///

        /// </summary>

        public void Reset()

        {

            index = -;

        }

    }

var strArr = new string[] { "科比", "詹姆斯", "杜兰特", "诺维茨基", "东契奇", "卢比奥" };

            var persons = new Persons(strArr);

            foreach (var t in persons)

            {

                Console.WriteLine(t);

            }

            //foreachq其实大概就是执行了这段代码，只是不知道是什么时候执行的Reset()

            PersonEnumable personEnumable = new PersonEnumable(strArr);

            while (personEnumable.MoveNext())

            {

                Console.WriteLine(personEnumable.Current);

            }