How to use application resource files (.resx) to efficiently... You can use application resource files (.resx) to efficiently create a localizable Microsoft ASP.NET Web application. By using resource files, you can store localized values for controls. The localized values are based on a user’s language and culture. When you store localized values in resource files, ASP.NET can select the appropriate value at run time. ----------------------- This page describes how to create a localized resx file in Visual Studio.NET. essentially after the first resx default file is created you just copy it and insert an extension for the language code you are looking to support, make sure localization is turned on in your app and .net handles the rest.