CEL_Payroll/Payroll.BO/Basic/DateDifferenceInYearsMonthDays.cs

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

namespace Payroll.BO
{
    public struct DateDifferenceInYearsMonthDays
    {
        private readonly int years;
        private readonly int months;
        private readonly int days;
        private readonly int hours;
        private readonly int minutes;
        private readonly int seconds;
        private readonly int milliseconds;

        public DateDifferenceInYearsMonthDays(int years, int months, int days, int hours, int minutes, int seconds, int milliseconds)
        {
            this.years = years;
            this.months = months;
            this.days = days;
            this.hours = hours;
            this.minutes = minutes;
            this.seconds = seconds;
            this.milliseconds = milliseconds;
        }

        public int Years { get { return years; } }
        public int Months { get { return months; } }
        public int Days { get { return days; } }
        public int Hours { get { return hours; } }
        public int Minutes { get { return minutes; } }
        public int Seconds { get { return seconds; } }
        public int Milliseconds { get { return milliseconds; } }

        enum Phase { Years, Months, Days, Done }

        public static DateDifferenceInYearsMonthDays CompareDates(DateTime date1, DateTime date2)
        {

            if (date2 < date1)
            {
                DateTime sub = date1;
                date1 = date2;
                date2 = sub;
            }

            DateTime current = date2;
            int years = 0;
            int months = 0;
            int days = 0;

            Phase phase = Phase.Years;
            DateDifferenceInYearsMonthDays span = new DateDifferenceInYearsMonthDays();

            while (phase != Phase.Done)
            {
                switch (phase)
                {
                    case Phase.Years:
                        if (current.Year == 1 || current.AddYears(-1) < date1)
                        {
                            phase = Phase.Months;
                        }
                        else
                        {
                            current = current.AddYears(-1);
                            years++;
                        }
                        break;
                    case Phase.Months:
                        if (current.AddMonths(-1) < date1)
                        {
                            phase = Phase.Days;
                        }
                        else
                        {
                            current = current.AddMonths(-1);
                            months++;
                        }
                        break;
                    case Phase.Days:
                        if (current.AddDays(-1) < date1)
                        {
                            days++;
                            TimeSpan timespan = current - date1;
                            span = new DateDifferenceInYearsMonthDays(years, months, days, timespan.Hours, timespan.Minutes, timespan.Seconds, timespan.Milliseconds);
                            phase = Phase.Done;
                        }
                        else
                        {
                            current = current.AddDays(-1);
                            days++;
                        }
                        break;
                }
            }

            return span;
        }
    }
       
}