/// <summary>
    /// 作为精确定时器的每秒激发事件
    /// <para>SystemTimer的每1000ms有大约15ms误差的问题。</para>
    /// </summary>
    public class AccuTimer
    {
        private System.Threading.Thread backThread;

        /// <summary>
        /// 每秒激发事件
        /// </summary>
        public event Action ElapsedPreSecond;

        /// <summary>
        /// 是否可用
        /// </summary>
        public bool Enable = true;

        /// <summary>
        /// 开始
        /// </summary>
        public void Start()
        {
            Enable = true;
            if (backThread == null)
            {
                backThread = new System.Threading.Thread(InnerLoop);
                backThread.IsBackground = true;
                backThread.Start();
            }
        }

        /// <summary>
        /// 停止
        /// </summary>
        public void Stop()
        {
            Enable = false;
        }

        private void InnerLoop()
        {
            DateTime preTime = DateTime.Now;
            while (true)
            {
                try
                {
                    //每当秒数变化即激发事件
                    DateTime curTime = DateTime.Now;
                    if (Math.Abs(curTime.Second - preTime.Second + 60) % 60 >= 1)
                    {
                        preTime = curTime;

                        if (Enable && ElapsedPreSecond != null)
                        {
                            System.Threading.ThreadPool.QueueUserWorkItem(o =>
                            {
                                ElapsedPreSecond.Invoke();
                            });
                        }
                    }
                }
                catch
                {
                }
                finally
                {
                    //尽量小的间隔去监视秒数变化
                    System.Threading.Thread.Sleep(50);
                }
            }
        }
    }