somnet的专栏

private static DateTime? 某年某月第几个星期几是几号(int year,int month,int weekIndex,DayOfWeek week)         {             DateTime date = new DateTime(year, month, 1);             int startWeek = (int)date.Day

private static int 第几个星期几(DateTime date, DayOfWeek week)         {             int month = date.Month;             if (date.DayOfWeek != week)                 return 0;             for (int i = 1