/// <summary>
    /// 订单助手
    /// </summary>
    public class OrderHelper
    {
        /// <summary>
        ///  防止创建类的实例
        /// </summary>
        private OrderHelper() { }

        private static readonly object Locker = new object();
        private static int _sn = 0;

        /// <summary>
        /// 生成订单编号
        /// </summary>
        /// <returns></returns>
        public static string GenerateId()
        {
            lock (Locker)   //lock 关键字可确保当一个线程位于代码的临界区时，另一个线程不会进入该临界区。
            {
                if (_sn == int.MaxValue)
                {
                    _sn = 0;
                }
                else
                {
                    _sn++;
                }
                
                Thread.Sleep(100);

                return "Wen" + DateTime.Now.ToString("yyyyMMddHHmmss")+ _sn.ToString().PadLeft(10, '0');
            }
        } 
    }