延时方法非阻塞， thread sleep会阻塞导致界面无法显示

        #region 延时方法非阻塞， thread sleep会阻塞导致界面无法显示
        public static void Delay(int mm)
        {
            DateTime current = DateTime.Now;
            while (current.AddMilliseconds(mm) > DateTime.Now)
            {
                Application.DoEvents();
            }
            return;
        }
        #endregion