For an Windows app, the option for the default language is found in Package.appxmanifest under the project. However, I do not know where to find the setting for a class library, because there is nothing like Package.appxmanifest under a class library project.
As a result, after I add Strings\zh-CN\Resources.resw and a few strings into a class library project, I get a few warnings, saying:
MakePRI : warning 0xdef00522: Resources found for language(s) 'zh-cn' but no resources found for default language(s): 'en-US'. Change the default language or qualify resources with the default language. http://go.microsoft.com/fwlink/?LinkId=231899
MakePRI : warning 0xdef01051: No default or neutral resource given for '...'. The application may throw an exception for certain user configurations when retrieving the resources.
No actual help from "fwlink" as usual.
Although nothing bad actually happens because the app gets zh-CN as its default language, it is still quite annoying and I would like to eliminate the warnings to turn on "treat warnings as errors".