Writing files using predefined dataformat strings

[kb-1000]

The neat part about them is that they are locale-specific, so if I use, for example, 22 as the data format id without specifying the format string, it'll display a datetime value using the user's localized date+time format. That's significantly nicer to deal with than needing to handle format string localization on the generating application side.
I'm not 100% sure how this should be handled API-side, though... would a format method with an int argument and a class with constants suffice?