I'm trying to check if current device culture use km or miles unit, based on this post i used RegionInfo.CurrentRegion.IsMetric but it always return True (Tryed on en_GB and fr_FR). There is another way to do this?
It returns true for en_GB because the United Kingdom is officially moving to the metric system.
If you want to create your own rules, you can build upon an existing culture, as outlined in an earlier answer: Create custom culture in ASP.NET