CurrentCulture
is the .NET representation of the default user locale of the system. This controls default number and date formatting and the like.
CurrentUICulture
refers to the default user interface language, a setting introduced in Windows 2000. This is primarily regarding the UI localization/translation part of your app.
Whatever regional options the system is configured to have will be the "Current" values in your .NET app.
Often times they are both the same. But on my system they would be different: I prefer my numbers and dates in the German format, so the CurrentCulture
would be German, but I also prefer all my applications in English, so the CurrentUICulture
would be English.
There is a nice article on the topic: Sorting it all Out: Why we have both CurrentCulture and CurrentUICulture.