Question

So, I have a few resource files for localization. They’re strings that can be formatted.

For example:

MyResource.resx
 Title: "MyApp - Ver: {0}"

I then return it by doing like so:

public String Title
{
    get { return String.Format(CultureInfo.CurrentUICulture, MyResources.Title, 1); }
}

I understand the difference between CurrentUICulture and CurrentCulture, but FxCop is telling me to use CurrentCulture instead?

Answer 1

To some extent FxCop is right: you should not use CurrentUICulture in this case. As others already said, CurrentCulture is meant for Locale-aware formatting, whereas CurrentUICulture is meant for reading translatable strings from resources.
What you did here, was formatting number, therefore FxCop complains that you used incorrect CultureInfo. Unfortunately, what FxCop did not tell you is, you should in fact use CultureInfo.InvariantCulture. Why? Because version number is something that does not depend on Locale. You will always see something like 1.9 and not something like 1,9. Thus InvariantCulture is the way to go.
Microsoft even provided specific class to store version information – oddly enough its name is Version (AFAIR it is in System namespace). This will always present you version numbers like I mentioned before, when you do ToString(). Its constructor also expects Locale-invariant version string when you instantiate it.