We're confronted with the following situation on the calendar popup of the schedule view we use in one of our Silverlight applications.
Depending on the culture, the calendar shows that year 2015 has 52 or 53 weeks. For instance if we switch the culture to France "fr", then there are 52 week, but for German "de" there are 53 weeks (see attached screenshots).
According to ISO 8601 https://en.wikipedia.org/wiki/ISO_8601#Week_dates year 2015 has 53 weeks because the last Thursday of the year is on 31.12.2015.
According to the MSDN documentation https://msdn.microsoft.com/en-us/library/system.globalization.calendarweekrule.aspx and this posting http://blogs.msdn.com/b/shawnste/archive/2006/01/24/iso-8601-week-of-year-format-in-microsoft-net.aspx the .NET framework "does not map exactly to ISO 8601".
Is there a way on how to influence the calendar in the schedule view to adhere to the ISO 8601 for cultures which respect it?
Is it possible somehow to implement the workaround described in the blog entry mentioned above?
Is there another reason why it differs between German and French cultures?
Here is how the number of weeks are by the cultures we tested with:
EN - US : 52
EN - UK : 52
DE - DE : 53
DE - CH : 53
ES : 52
FR : 52
IT : 53
NL : 53
CZ : 52
PL : 53
HU : 52