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Posted 28 Feb 2005

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C# DateTime Library

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19 Dec 2005
Common DateTime routines for C#.

Introduction

I recently made the transition from Delphi to C#. I noticed that some of the datetime utilities that I used to use were not available in C#. So I recreated them. Hopefully this will save someone some time in the future.

The Code

C#
using System;
namespace Concepts2Code.Utilities
{
    /// <summary>
    /// Common DateTime Methods.
    /// </summary>
    /// 

    public enum Quarter
    {
        First = 1,
        Second = 2,
        Third = 3,
        Fourth = 4
    }

    public enum Month
    {
        January = 1,
        February = 2,
        March = 3,
        April = 4,
        May = 5,
        June = 6,
        July = 7,
        August = 8,
        September = 9,
        October = 10,
        November = 11,
        December = 12
    }

    public class DateUtilities
    {
        #region Quarters

        public static DateTime GetStartOfQuarter( int Year, Quarter Qtr )
        {
            if( Qtr == Quarter.First )    // 1st Quarter = January 1 to March 31
                return new DateTime( Year, 1, 1, 0, 0, 0, 0 );
            else if( Qtr == Quarter.Second ) // 2nd Quarter = April 1 to June 30
                return new DateTime( Year, 4, 1, 0, 0, 0, 0 );
            else if( Qtr == Quarter.Third ) // 3rd Quarter = July 1 to September 30
                return new DateTime( Year, 7, 1, 0, 0, 0, 0 );
            else // 4th Quarter = October 1 to December 31
                return new DateTime( Year, 10, 1, 0, 0, 0, 0 );
        }

        public static DateTime GetEndOfQuarter( int Year, Quarter Qtr )
        {
            if( Qtr == Quarter.First )    // 1st Quarter = January 1 to March 31
                return new DateTime( Year, 3, 
                       DateTime.DaysInMonth( Year, 3 ), 23, 59, 59, 999 );
            else if( Qtr == Quarter.Second ) // 2nd Quarter = April 1 to June 30
                return new DateTime( Year, 6, 
                       DateTime.DaysInMonth( Year, 6 ), 23, 59, 59, 999 );
            else if( Qtr == Quarter.Third ) // 3rd Quarter = July 1 to September 30
                return new DateTime( Year, 9, 
                       DateTime.DaysInMonth( Year, 9 ), 23, 59, 59, 999 );
            else // 4th Quarter = October 1 to December 31
                return new DateTime( Year, 12, 
                       DateTime.DaysInMonth( Year, 12 ), 23, 59, 59, 999 );
        }

        public static Quarter GetQuarter( Month Month )
        {
            if( Month <= Month.March )
            // 1st Quarter = January 1 to March 31
                return Quarter.First;
            else if( ( Month >= Month.April ) && ( Month <= Month.June ) )
            // 2nd Quarter = April 1 to June 30
                return Quarter.Second;
            else if( ( Month >= Month.July ) && ( Month <= Month.September ) )
            // 3rd Quarter = July 1 to September 30
                return Quarter.Third;
            else // 4th Quarter = October 1 to December 31
                return Quarter.Fourth;
        }

        public static DateTime GetEndOfLastQuarter()
        {                 
            if( (Month)DateTime.Now.Month <= Month.March )
            //go to last quarter of previous year
                return GetEndOfQuarter( DateTime.Now.Year - 1, Quarter.Fourth);
            else //return last quarter of current year
                return GetEndOfQuarter( DateTime.Now.Year, 
                  GetQuarter( (Month)DateTime.Now.Month));
        }

        public static DateTime GetStartOfLastQuarter()
        {
            if( (Month)DateTime.Now.Month <= Month.March )
            //go to last quarter of previous year
                return GetStartOfQuarter( DateTime.Now.Year - 1, Quarter.Fourth);
            else //return last quarter of current year
                return GetStartOfQuarter( DateTime.Now.Year, 
                  GetQuarter( (Month)DateTime.Now.Month));
        }

        public static DateTime GetStartOfCurrentQuarter()
        {
            return GetStartOfQuarter( DateTime.Now.Year, 
                   GetQuarter( (Month)DateTime.Now.Month ));
        }

        public static DateTime GetEndOfCurrentQuarter()
        {
            return GetEndOfQuarter( DateTime.Now.Year, 
                   GetQuarter( (Month)DateTime.Now.Month ));
        }
        #endregion

        #region Weeks
        public static DateTime GetStartOfLastWeek()
        {
            int DaysToSubtract = (int)DateTime.Now.DayOfWeek + 7;
            DateTime dt = 
              DateTime.Now.Subtract(System.TimeSpan.FromDays( DaysToSubtract ) );
            return new DateTime( dt.Year, dt.Month, dt.Day, 0, 0, 0, 0 );
        }

        public static DateTime GetEndOfLastWeek()
        {
            DateTime dt = GetStartOfLastWeek().AddDays(6);
            return new DateTime( dt.Year, dt.Month, dt.Day, 23, 59, 59, 999 );
        }

        public static DateTime GetStartOfCurrentWeek()
        {
            int DaysToSubtract = (int)DateTime.Now.DayOfWeek ;
            DateTime dt = 
              DateTime.Now.Subtract( System.TimeSpan.FromDays( DaysToSubtract ) );
            return new DateTime( dt.Year, dt.Month, dt.Day, 0, 0, 0, 0 );
        }

        public static DateTime GetEndOfCurrentWeek()
        {
            DateTime dt = GetStartOfCurrentWeek().AddDays(6);
            return new DateTime( dt.Year, dt.Month, dt.Day, 23, 59, 59, 999 );
        }
        #endregion

        #region Months

        public static DateTime GetStartOfMonth( Month Month, int Year )
        {
             return new DateTime( Year, (int)Month, 1, 0, 0, 0, 0 );
        }

        public static DateTime GetEndOfMonth( Month Month, int Year )
        {
            return new DateTime( Year, (int)Month, 
               DateTime.DaysInMonth( Year, (int)Month ), 23, 59, 59, 999 );
        }

        public static DateTime GetStartOfLastMonth()
        {
            if( DateTime.Now.Month == 1 )
                return GetStartOfMonth( 12, DateTime.Now.Year - 1);
            else
                return GetStartOfMonth( DateTime.Now.Month -1, DateTime.Now.Year );
        }

        public static DateTime GetEndOfLastMonth()
        {
            if( DateTime.Now.Month == 1 )
                return GetEndOfMonth( 12, DateTime.Now.Year - 1);
            else
                return GetEndOfMonth( DateTime.Now.Month -1, DateTime.Now.Year );
        }

        public static DateTime GetStartOfCurrentMonth()
        {
            return GetStartOfMonth( DateTime.Now.Month, DateTime.Now.Year );
        }

        public static DateTime GetEndOfCurrentMonth()
        {
            return GetEndOfMonth( DateTime.Now.Month, DateTime.Now.Year );
        }
        #endregion

        #region Years
        public static DateTime GetStartOfYear( int Year )
        {
            return new DateTime( Year, 1, 1, 0, 0, 0, 0 );
        }

        public static DateTime GetEndOfYear( int Year )
        {
            return new DateTime( Year, 12, 
              DateTime.DaysInMonth( Year, 12 ), 23, 59, 59, 999 );
        }

        public static DateTime GetStartOfLastYear()
        {
            return GetStartOfYear( DateTime.Now.Year - 1 );
        }

        public static DateTime GetEndOfLastYear()
        {
            return GetEndOfYear( DateTime.Now.Year - 1 );
        }

        public static DateTime GetStartOfCurrentYear()
        {
            return GetStartOfYear( DateTime.Now.Year );
        }

        public static DateTime GetEndOfCurrentYear()
        {
            return GetEndOfYear( DateTime.Now.Year );
        }
        #endregion        

        #region Days
        public static DateTime GetStartOfDay( DateTime date )
        {
            return new DateTime( date.Year, date.Month, date.Day, 0, 0, 0, 0 );
        }

        public static DateTime GetEndOfDay( DateTime date )
        {
            return new DateTime( date.Year, date.Month, 
                                 date.Day, 23, 59, 59, 999 );
        }
        #endregion
      }
}

License

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About the Author

Michael Ceranski
Software Developer (Senior) Concepts2Code
United States United States
Michael is the co-founder and master consultant for Concepts2Code, a software consulting company based in Buffalo, New York. He's been programming since the early 1990's. His vast programming experience includes VB, Delphi, C#, ASP, ASP.NET, Ruby on Rails, Coldfusion and PHP. Michael also is a Microsoft Certified Application Developer and a Certified Technology Specialist for SQL Server.

Visit his blog.

Comments and Discussions

 
QuestionUnit Tests? Pin
Bil Simser11-May-05 23:31
MemberBil Simser11-May-05 23:31 
GeneralSimplification Pin
Christian Falk12-Apr-05 20:50
MemberChristian Falk12-Apr-05 20:50 
GeneralFiscal Year vs Calendar Year Pin
Darren Pruitt14-Mar-05 4:23
MemberDarren Pruitt14-Mar-05 4:23 
GeneralRe: Fiscal Year vs Calendar Year Pin
Jani Giannoudis16-Mar-11 21:09
MemberJani Giannoudis16-Mar-11 21:09 
GeneralC# standards Pin
Drew Noakes11-Mar-05 0:12
MemberDrew Noakes11-Mar-05 0:12 
GeneralImprove readability... Pin
Alexander Turlov9-Mar-05 14:14
MemberAlexander Turlov9-Mar-05 14:14 
GeneralRe: Improve readability... Pin
Drew Noakes11-Mar-05 0:01
MemberDrew Noakes11-Mar-05 0:01 
GeneralSome useful methods else... Pin
Alexander Turlov9-Mar-05 14:02
MemberAlexander Turlov9-Mar-05 14:02 
GeneralUNIX-like timestamp conversions Pin
Ionut FIlip7-Mar-05 19:45
MemberIonut FIlip7-Mar-05 19:45 
GeneralRe: UNIX-like timestamp conversions Pin
Richard Deeming9-Mar-05 2:45
mveRichard Deeming9-Mar-05 2:45 
GeneralAnother simplification Pin
mav.northwind1-Mar-05 0:42
Membermav.northwind1-Mar-05 0:42 
GeneralSimplification idea... Pin
Marc Brooks28-Feb-05 10:54
MemberMarc Brooks28-Feb-05 10:54 
GeneralConfused Pin
Robert Rohde28-Feb-05 6:53
MemberRobert Rohde28-Feb-05 6:53 
GeneralRe: Confused Pin
mceranski28-Feb-05 8:54
Membermceranski28-Feb-05 8:54 
GeneralRe: Confused Pin
Drew Noakes11-Mar-05 0:16
MemberDrew Noakes11-Mar-05 0:16 

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