Gregorian Calendar - GetWeekOfYear for 2005

[bp]

I'm using the System.Globalization.GregorianCalendar class to calculate
week numbers. My weeks begin on Saturday and follow the "first four
day" rule.

GregorianCalendar cal = new GregorianCalendar();
week = cal.GetWeekOfYear("12/31/2005",
CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Saturday);

GetWeekOfYear() returns "53" for "12/31/2005", even though there are
only 52 weeks in 2005. "12/30/2005" correctly returns "52", and
"1/1/2006" correctly returns "1".

Can someone explain this to me? Is this intended behavior or is this a
bug in the GregorianCalendar class?

Thanks in advance.

 

[Ryan Trudelle-Schwarz]

I'm using the System.Globalization.GregorianCalendar class to

calculate week numbers. My weeks begin on Saturday and follow the
"first four day" rule.

GregorianCalendar cal = new GregorianCalendar();
week = cal.GetWeekOfYear("12/31/2005",
CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Saturday);
GetWeekOfYear() returns "53" for "12/31/2005", even though there are
only 52 weeks in 2005. "12/30/2005" correctly returns "52", and
"1/1/2006" correctly returns "1".

Can someone explain this to me? Is this intended behavior or is this
a bug in the GregorianCalendar class?

Thanks in advance.

Check it on a calendar, looks correct to me.
12/30 is a Friday, the end of the 52nd week.
12/31 is a Saturday, the beginning of the 53rd week (1 day week).

 

[bp]

The project I'm working on is a fiscal calendar that doesn't provide
for "partial weeks" (ie. a week with less than 7 days). In this case I
want "12/31/2005" to be the first day of fiscal week "1" for 2006. The
first week of 2006 would be the week beginning on "12/31/2005" because
that week contains "4 or more" days in January...
I see now that this is not how the GregorianCalendar works...do you
know if there's another calendar with a GetWeekOfYear() method
supporting this calculation?
Thanks for the response.

 

[Manohar Kamath]

One way to handle this is check the week of 1/1/2006, and also the DayOfWeek
for 1/1/2006. If it returns 3 or more (wednesday or later), add 1 to the
week count, and thus get the correct fiscal week.