C# Code to get First Working Day of the Month and Year excluding holidays and weekends

public DateTime GetFirstWorkingDay(int year, int month)

        {          

            DateTime FirstBusinessDay = default(DateTime);

            FirstBusinessDay = new DateTime(year, month, 1);

            while (IsHoliday(FirstBusinessDay) || IsWeekEnd(FirstBusinessDay))

            {

                FirstBusinessDay = FirstBusinessDay.AddDays(1);

            }

            return FirstBusinessDay;

        }

        private bool IsHoliday(DateTime date)

        {

            bool isHoliday = false;

            //Jan 1st -- Holiday

            if (date.Month == 1 && date.Day == 1)

                isHoliday = true;

            //July 4th -- Independence Day

            if (date.Month == 7 && date.Day == 4)

                isHoliday = true;

            //LABOR DAY -- 1st Monday in September

            DateTime laborDay = new DateTime(date.Year, 9, 1);

            DayOfWeek dayOfWeek = laborDay.DayOfWeek;

            while (dayOfWeek != DayOfWeek.Monday)

            {

                laborDay = laborDay.AddDays(1);

                dayOfWeek = laborDay.DayOfWeek;

            }

            if (date == laborDay.Date)

                isHoliday = true;

            return isHoliday;

        }

        private bool IsWeekEnd(DateTime date)

        {

            return date.DayOfWeek == DayOfWeek.Saturday

                || date.DayOfWeek == DayOfWeek.Sunday;

        }