BusinessDays and BusinessHourHours Extension methods for DateTime

DateTimeExtensions.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace DateTimeExtensionTest
{
    public static class DateTimeExtensions
    {

        public static int GetBusinessDays(this DateTime startDate, DateTime endDate, IEnumerable<DateTime> holidays)
    {
        if (startDate > endDate)
        {
            throw new NotSupportedException("ERROR: [startDate] cannot be greater than [endDate].");
        }

        int cnt = 0;
        for (var current = startDate; current < endDate; current = current.AddDays(1))
        {
            if (current.DayOfWeek != DayOfWeek.Saturday && current.DayOfWeek != DayOfWeek.Sunday && (holidays != null && !holidays.Contains(current.Date))) 
            { 
                cnt++;
            }
        }
        return cnt;
    }

    public static int GetBusinessHours(this DateTime startDate, DateTime endDate, IEnumerable<DateTime> holidays)
    {
        if (startDate > endDate)
        {
            throw new NotSupportedException("ERROR: [startDate] cannot be greater than [endDate].");
        }

        int cnt = -1;
        for (var current = startDate; current < endDate; current = current.AddHours(1))
        {
            if (current.DayOfWeek != DayOfWeek.Saturday && current.DayOfWeek != DayOfWeek.Sunday && (holidays != null && !holidays.Contains(current.Date))) 
            { 
                cnt++;
            }
        }
        return cnt;
    }

    }
}