C#週數
1.
System.Globalization.GregorianCalendar gc = new System.Globalization.GregorianCalendar();
int weekOfYear = gc.GetWeekOfYear(DateTime.Now, System.Globalization.CalendarWeekRule.FirstDay, DayOfWeek.Monday);//0:sunday,1:monday
string week = Convert.ToString(weekOfYear);
if (week.Length == 1)
{
week = '0' + week;
}
DateCode = DateTime.Now.Year.ToString().Substring(2, 2) + week;