Chapter 08. DateTime and culture specific formatting

[Dreamoochy]

I have French interface language in my OS (along with English), as well as french regional formats.
When I run "Christmas" example, i get

Christmas: dimanche, 25 decembre 2022
Christmas is in month 12 of the year.
Christmas is day 359 of the year.
Christmas 2022 is on a Sunday.

Note that the first line shows weekday and month in French, while the last one - in English.
So default formatting is culture-specific, while the one with christmas.DayOfYear appears to be culture-invariant. But why does the program use different cultures without any intentional switching made by a programmer?

[markjprice]

I think you mean DayOfWeek. DayOfYear is a number between 1 and 366. DateTime.DayOfWeek returns an enum and they cannot be localized so they are in effect always culture-invariant. You would need to use a format code like the first example instead.

[markjprice]

I will add a paragraph about this in the next edition because it is an interesting example that I'm sure lots of people are confused by.

[markjprice]

You could also use the following to localize the enum value:

WriteLine("Christmas {0} is on a {1}.",
  arg0: christmas.Year,
  arg1: DateTimeFormatInfo.CurrentInfo.GetDayName(christmas.DayOfWeek));

And to get the abbreviated name:

DateTimeFormatInfo.CurrentInfo.GetAbbreviatedDayName(christmas.DayOfWeek)