I have a feeling this is something very obvious that I'm missing, but here goes.
I'm trying to set up multiple languages in an ASP.Net MVC project (C#, MVC2, .Net4.0). However, I have some cases where I want to have phrases translated within the Controller (error/success messages, mostly). However, it seems every method I try is either protected or internal. How do I access the resx files from within my Controller?
Make sure the modifier on the resx class that's created for you is Public. When you're editing the resx file, you'll see a drop down with the modifier towards the top right (close to the vertical middle of your screen).
However, consider the fact that you could have your ViewModel take care of localizing validation messages by decorating the different properties with DataAnnotations and resource files.
This is a presentation specific concern, I think the best approach is to handle this at a View level. You will have less problems if you access resources from the View. Also note that accessing resources from the controllers make them less testable, because when accessing a resource (by default) the resource manager looks for a specific file which is not found when you´re testing.