I have a second resx file Strings.ps-ps.resx that I want to point my code to at runtime. Each resx has Designer.cs with a unique class name. Do I have to switch/wrap these
You need to change your UI Culture to use a different resx file. This can be done in config
or in code
Thread.CurrentThread.CurrentUICulture = new CultureInfo("fr-FR");;
If you want to automatically adapt to the user, you can query the HttpContext.Current.Request.UserLanguages for the users browser settings