C# 中實現 foreach 功能

1. MySplit 類

    /// <summary>
    /// MySplit 類
    /// </summary>
    public class MySplit : IEnumerable
    {
        private string[] elements;

        public MySplit(string source, char[] delimiters)
        {
            elements = source.Split(delimiters);
        }

        IEnumerator IEnumerable.GetEnumerator()
        {
            return new MyEnumerator(this);
        }

        #region 在嵌套類中實現 IEnumerator 介面
        /// <summary>
        /// 在嵌套類中實現 IEnumerator 介面，以便以後方便建立多個枚舉
        /// </summary>
        public class MyEnumerator : IEnumerator
        {
            private int position = -1;
            private MySplit t;

            public MyEnumerator(MySplit t)
            {
                this.t = t;
            }

            public bool MoveNext()
            {
                if (position < t.elements.Length - 1)
                {
                    position++;
                    return true;
                }
                else
                {
                    return false;
                }
            }

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

            object IEnumerator.Current
            {
                get
                {
                    try
                    {
                        return t.elements[position];
                    }
                    catch (IndexOutOfRangeException)
                    {
                        throw new InvalidOperationException();
                    }
                }
            }
        }
        #endregion
    }

2. 使用

    MySplit mySplit = new MySplit("大豆男生: I Love You!", new char[] { ' ', '-' });
    foreach (string item in mySplit)
    {
        Console.WriteLine(item);
    }

3. 輸出結果
   大豆男生:
   I
   Love
   You!

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本文地址：http://www.cnblogs.com/anjou/archive/2007/07/05/807357.html