A Date and Time formatter

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Introduction

This class formats into strings COleDateTime objects. It uses the commonly defined formatting options such as MM-dd-yy or hh:mm:ss.

Background

There is no single Win32 API function that will handle both date and time formatting in the same place. The Win32 API supports the GetDateFormat and the GetTimeFormat functions, but they have to be used separately. Worse, if the programmer wants to provide the user with a single date and time formatting string, he or she will have to split it and provide each function, its part of the format string. This class was created to address this issue.

Using the class

The class is very simple to use. Start by instantiating a CDateTimeFormat object:

CDateTimeFormat dtf;

This object may be used for more than one format. The second thing is to set the COleDateTime object:

dtf.SetDateTime(odtDateTime);

This method takes a reference for speed. Next, you set the format string:

dtf.SetFormat(_T("MM-dd-yyyy"));

Now, you only need to get the formatted string, using:

CString strFormat = dtf.GetString();

If you do not want to pay for a CString copy when retrieving the formatted string, you can also give the object a pointer to your TCHAR buffer by using:

TCHAR szMyBuffer[256];
dtf.SetFormatBuf(szMyBuffer);

You should allocate enough space for the format strings. The default allocation in the format object is 256 characters.

Formatting syntax

The formatting syntax is based on the DateTimePicker control. The following table (transcribed from MSDN) contains all the supported formatting controls:

Element	Description
d	The one- or two-digit day.
dd	The two-digit day. Single-digit day values are preceded by a zero.
ddd	The three-character weekday abbreviation.
dddd	The full weekday name.
w	Single or double digit week number.
ww	Double digit week number.
h	The one- or two-digit hour in 12-hour format.
hh	The two-digit hour in 12-hour format. Single-digit values are preceded by a zero.
H	The one- or two-digit hour in 24-hour format.
HH	The two-digit hour in 24-hour format. Single-digit values are preceded by a zero.
m	The one- or two-digit minute.
mm	The two-digit minute. Single-digit values are preceded by a zero.
M	The one- or two-digit month number.
MM	The two-digit month number. Single-digit values are preceded by a zero.
MMM	The three-character month abbreviation.
MMMM	The full month name.
q	Single digit quarter number.
t	The one-letter AM/PM abbreviation (that is, AM is displayed as "A").
tt	The two-letter AM/PM abbreviation (that is, AM is displayed as "AM").
yy	The last two digits of the year (that is, 1996 would be displayed as "96").
yyyy	The full year (that is, 1996 would be displayed as "1996").
'	Enter literal mode. All characters are copied to the format string up to the next single quote.
\	Enter literal mode for the next character only (escape).

Locale usage

This class makes heavy use of the GetLocaleInfo API, using the LOCALE_SYSTEM_DEFAULT. This can be changed to match your needs.

Speed optimizations

Speed may be optimized by pre-caching all locale data on the first instantiation. This will be added in the next release.

Revisions

2003-02-20: Added support for week number and quarter number formatting.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

About the Author

Joao Paulo Figueira

Software Developer
Primeworks

Portugal

Member

João is a partner at Primeworks, a company that develops remote database access software for Windows Mobile. He also works for Frotcom, a company that develops web-based fleet management solutions.

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Wrong weeknumber

tom.schultz

1:43 3 Feb '05

I keep getting the wrong week number. It seems consistent if the previous year had 53 weeks. Noticed the inconsistency between the CMonthCtrl and your code. Is there an easy fix?
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Re: Wrong weeknumber

João Paulo Figueira

3:10 3 Feb '05

Gee... I never noticed that. I'll have a look. Regards, João Paulo Figueira Embedded MVP
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Fix

tom.schultz

21:46 7 Apr '05

I've been using this fix for some time, it works...
You did not take into the consideration that you'd have a week 53



void CDateTimeFormat::FormatWeek()

{

	TCHAR			szFmt[16];

	int				nDayOfYear = m_odt.GetDayOfYear(),

					nWeek,

					nfday,

					dow;

	COleDateTime	odtFirst(m_odt.GetYear(), 1, 1, 0, 0, 0);

 

	nWeek = ((nDayOfYear) / 7) + 1;

	nfday = odtFirst.GetDayOfWeek();

	dow = m_odt.GetDayOfWeek();

 

        //Change weekday ordering, monday first (day 1), sunday(day 7)

	if (nfday == 1) nfday = 7; 

	else

		nfday --;

 

        //Change weekday ordering, monday first (day 1), sunday(day 7)

	if (dow == 1) dow = 7;

	else

		dow --;

 

        //If week 53 exists, and we're on a thursday or later... (this is where the error would occur.)

	if ( nfday >= 4 && dow > 4)

		nWeek --;

 

	switch(m_nw)

	{

	case 1:

		swprintf(szFmt, _T("%d"), nWeek);

		break;

 

	case 2:

		swprintf(szFmt, _T("%02d"), nWeek);

		break;

 

	default:

		wcscpy(szFmt, _T("???"));

	}

 

	wcscat(m_pszBuf, szFmt);

}

Hope it helps someone.... just copy and paste.

Re: Fix

João Paulo Figueira

21:55 7 Apr '05

Thank you! Regards, João Paulo Figueira Embedded MVP
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Re: Fix

tom.schultz

1:34 20 Mar '06

I just discovered a rather embarresing error in my "fix". I have now created my own class that will return the WeekOfYear. I'll paste the important code here, as a remedy (hopefully).

	

CDateTime CDateTime::GetDate1stDay1stWeek()

{

	TCHAR				szBuf[20];

	CDateTime			odt1stJan(this->GetYear(), 1, 1, 0, 0, 0);

	CDateTime			odt1stDay1stWeek;

	COleDateTimeSpan	span;

 

	int				n1stWoY;

	int				dow1stJan, n1stDayofWeek;

	GetLocaleInfo(LOCALE_USER_DEFAULT, LOCALE_IFIRSTWEEKOFYEAR, szBuf, sizeof(szBuf)/sizeof(TCHAR));

	n1stWoY = _ttoi(szBuf);

			

	GetLocaleInfo(LOCALE_USER_DEFAULT, LOCALE_IFIRSTDAYOFWEEK, szBuf, sizeof(szBuf)/sizeof(TCHAR));

	n1stDayofWeek = _ttoi(szBuf);

			

	dow1stJan = odt1stJan.GetDayOfWeek();

 

	//convert to (mon(0) .. sun(6)) COleDateTime uses U.S or M$ standard.

	if ( dow1stJan == 1)

		dow1stJan = 6;

	else

		dow1stJan-=2;

	//convertion done.

 

	/*

		0 Week containing 1/1 is the first week of that year. 

		1 First full week following 1/1 is the first week of that year 

		2 First week containing at least 4 days is the first week of that year. 

	*/

 

	switch ( n1stWoY )

	{

		case 0 : //Week one always start in the week where 1.jan is.

			if ( n1stDayofWeek > dow1stJan )

			{

				span.SetDateTimeSpan( 7 - (n1stDayofWeek - dow1stJan), 0,0,0 );

			}

			else

			{

				span.SetDateTimeSpan( (dow1stJan - n1stDayofWeek), 0,0,0 );

			}

			odt1stDay1stWeek = odt1stJan - span;

			break;

 

		case 1 : //First week containing only days from this year.

			if ( dow1stJan == n1stDayofWeek) 

				odt1stDay1stWeek = odt1stJan;

			else				 // find next full week.

			{ //Find No. days to first day of next week.

				span.SetDateTimeSpan( 7 + (n1stDayofWeek - dow1stJan), 0,0,0 );

				odt1stDay1stWeek = odt1stJan + span;

			}

			break;

		case 2 : //First week containing at least 4 days of current year.

			if ( dow1stJan == n1stDayofWeek)	//the whole week in this year.

				odt1stDay1stWeek = odt1stJan;

			else

			{

				int diff;

				if (n1stDayofWeek > dow1stJan)

					diff = (7 + dow1stJan) - n1stDayofWeek;

				else

					diff = dow1stJan - n1stDayofWeek;

 

				if ( (diff <= 3) )

					span.SetDateTimeSpan( -diff, 0,0,0 );	//correct week just adjust for first dow.

				else

				{

					span.SetDateTimeSpan( 7 - diff, 0,0,0 );	//we need to skip to first day of next week.

				}

								

				odt1stDay1stWeek = odt1stJan + span;

			}

			break;		

	};

	return odt1stDay1stWeek;

}

 

int CDateTime::GetWeekOfYear()

{

	CDateTime			Jan1stNxtYear( GetYear()+1, 01, 01, 00, 00, 00 );

	CDateTime			odt1stDay1stWeekNextYear = Jan1stNxtYear.GetDate1stDay1stWeek();

	CDateTime			odt1stDay1stWeek = GetDate1stDay1stWeek();

	COleDateTimeSpan	        span, span1Day(1,0,0,0);

 

	int nWeek(-1);

 

	if ( odt1stDay1stWeek > (*this) )

	{

		CDateTime newYearsEve( GetYear() - 1, 12, 31, 00, 00, 00 );

		nWeek = newYearsEve.GetWeekOfYear();

	} else if ( odt1stDay1stWeekNextYear <= (*this) ) //we're in week 1.

	{

		nWeek = 1;

	} else 

	{

		span = (*this) - odt1stDay1stWeek; // find the span in days between (1day of 1st week) and current day. 

		nWeek =  ( (span.GetDays() / 7) +1);

	}

	return nWeek;

}

 

//And format..

CString CDateTime::Format( LPCTSTR pFormat )

{

	CDateTimeFormat frmt;

	frmt.SetDateTime( (*this) );

	frmt.SetFormat( pFormat );

	return frmt.GetString();

}

now i change the Date Timeformatter to use my COleDateTime derived class instead. So the code reads.



void CDateTimeFormat::FormatWeek()

{

	TCHAR			szFmt[16];

 



 

	switch(m_nw)

	{

	case 1:

		swprintf(szFmt, _T("%d"), m_odt.GetWeekOfYear());

		break;

 

	case 2:

		swprintf(szFmt, _T("%02d"), m_odt.GetWeekOfYear());

		break;

 

	default:

		wcscpy(szFmt, _T("???"));

	}

 

	wcscat(m_pszBuf, szFmt);

}

-- modified at 7:36 Monday 20th March, 2006

how to get 'seconds' ?

riki_risnandar

17:20 1 Jan '05

the class doesnt get the 'seconds' and 'miliseconds' format.. how can i do that ? Riki Risnandar
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Re: how to get 'seconds' ?

João Paulo Figueira

0:41 2 Jan '05

The seconds format is either 'ss' or 's'. There is no provision for milliseconds. Regards, João Paulo Figueira Embedded MVP
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Date time picker Win 32 API

Anonymous

19:59 22 Apr '03

I have problems in using date time picker control with Win 32 API programming. Can anybody help?
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Re: Date time picker Win 32 API

SiyaulHaqu

4:21 13 Aug '07

Still waiting for the reply ?? Have a look at http://www.gamedev.net/community/forums/topic.asp?topic_id=197227[^]
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ANSI C strftime() does this too....

Harald Krause

0:28 7 Feb '03

... and much more... bb \|~ bb
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Re: ANSI C strftime() does this too....

João Paulo Figueira

0:38 7 Feb '03

Yeah, but I is not supported in the embedded version of the API for PocketPC (or so the documentation says). Maybe this should go to the embedded section...
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Re: ANSI C strftime() does this too....

Brian van der Beek

9:17 9 Feb '03

I believe COleDateTime is supprted by WinCE. This class can do the same, if you don't mind using MFC that is.
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Re: ANSI C strftime() does this too....

João Paulo Figueira

10:32 9 Feb '03

You should be right according to the documentation. Unfortunately, MFC for CE 3.0 gives COleDateTime the same treatment as to CTime: no configurable formatting methods. If you look at the COleDateTime definition in MFC for CE 3.0 (in afxdisp.h), you will see the following code:

 
// formatting
CString Format(DWORD dwFlags = 0, LCID lcid = LANG_USER_DEFAULT) const;
WCE_DEL	CString Format(LPCTSTR lpszFormat) const;
WCE_DEL	CString Format(UINT nFormatID) const;

The problem is that WCE_DEL expands to //...

Re: ANSI C strftime() does this too....

John A. Johnson

2:36 7 Feb '03

Different objectves: in my program code I'll use the "strftime()" function that is more powerfull, but if I have to ask the format to the end user, I prefer this article solution because is more similar to the Excel/Access style format.

And, because I really have to create a "properties" dialog in my project with the display format preference... I'll use this article for sure!

Big Grin | :-D

Ps: Thank you João Paulo Figueira!

Re: ANSI C strftime() does this too....

Harald Krause

2:44 7 Feb '03

Agree. But if I have to use some "Excel" style format, I do a simple reformat of the parameter string getting the strftime control string by string replace. This has many advantages: Very easy to localize (different languages) and still the power of strftime. bb \|~ bb
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Re: ANSI C strftime() does this too....

João Paulo Figueira

4:15 7 Feb '03

Thank you! You just named all the reasons that lead me to write this one.
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Re: ANSI C strftime() does this too....

Steve Mayfield

19:40 7 Feb '03

There is also CTime::Format()
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Re: ANSI C strftime() does this too....

João Paulo Figueira

6:11 8 Feb '03

This method is absent from MFC 3.0 for Windows CE 3.0. If you look at the class declaration in afx.h you will see something like:

 
    // formatting using "C" strftime
WCE_DEL CString Format(LPCTSTR pFormat) const;
WCE_DEL CString FormatGmt(LPCTSTR pFormat) const;
WCE_DEL CString Format(UINT nFormatID) const;
WCE_DEL CString FormatGmt(UINT nFormatID) const;

The WCE_DEL expands to //... Thank you, Microsoft!