string weekDayName = DateTime.Now.ToString("dddd"); // 輸出完整的星期名稱，如"星期一"
string[] days = new string[] { "星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六" };
int dayIdx = Convert.ToInt32(DateTime.Now.DayOfWeek);
string weekDay = days[dayIdx];