I just stumbled across a nice little hidden “feature” in the .NET framework. If you’re running on a machine that has the CurrentCulture set to fr-CA the default DateTimeFormatInfo.CurrentInfo.ShortDatePattern is dd-MM-yyyy. On my current project we wanted to allow the end user to override that value with their own format when a date is displayed on the screen. The easy way to do this is to do something like DateTime.Now.ToString(“dd/MM/yyyy”). Unfortunately the result from that will appear as 16-09-2010 still. As far as I can tell (and there is very little backing this up), this is by design. I’m not sure why at all. If the CurrentCulture is set to en-CA both the formats of dd/MM/yyyy and dd-MM-yyyy will cause .ToString() to output a value that you would expect, but as soon as you trip over to fr-CA the rules seem to change.

If you’re running into this there is a relatively simple solution. DateTime.Now.ToString(“dd\/MM\/yyyy”) will output 16/06/2010 as you’d expect.

The more localization that I’m doing on this application, the more I’m finding nice hidden gems of inconsistency like this.