Sådan får du 14 dage før den givne dato for at undgå helligdage

Jeg ville beregne datoen ved hjælp af en funktion som den nedenfor (som jeg bruger)

public static DateTime AddBusinessDays(DateTime date, int days)
 {
    if (days == 0) return date;

   if (date.DayOfWeek == DayOfWeek.Saturday)
   {
    date = date.AddDays(2);
    days -= 1;
  }
  else if (date.DayOfWeek == DayOfWeek.Sunday)
  {
    date = date.AddDays(1);
    days -= 1;
  } 



 date = date.AddDays(days / 5 * 7);
 int extraDays = days % 5;

 if ((int)date.DayOfWeek + extraDays > 5)
 {
    extraDays += 2;
 }

int extraDaysForHolidays =-1;
//Load holidays from DB into list
List<DateTime> dates = GetHolidays();

while(extraDaysForHolidays !=0)
{

 var days =  dates.Where(x => x >= date  && x <= date.AddDays(extraDays)).Count;
 extraDaysForHolidays =days;
 extraDays+=days;  
}


return date.AddDays(extraDays);

}

Har ikke testet ast-sektionen, der holder ferie