public TimeZoneInfo TimeZoneInfo
        {
            get
            {
                var timeZoneInfoString = _user.TimeZoneInfoString;
                if (!string.IsNullOrEmpty(timeZoneInfoString))
                {
                    try
                    {
                        return TimeZoneInfo.FindSystemTimeZoneById(timeZoneInfoString);
                    }
                    catch (TimeZoneNotFoundException exception)
                    {
                        LogManager.GetLogger(GetType()).Error(exception);
                    }
                    catch (Exception exception)
                    {
                        LogManager.GetLogger(GetType()).Error(exception);
                    }

                    return TimeZoneInfo.Local;
                }
                else
                {
                    LogManager.GetLogger(GetType()).ErrorFormat("timeZoneInfoString for user {0} is empty", HttpContext.Current.User.Identity.Name);
                    return TimeZoneInfo.Local;
                }
            }
        }

其中， _user.TimeZoneInfoString会存在数据库中