The Description and Inherits attributes can be declared together in the same @ Application directive, as shown in the Example section.
If you want to use code separation for the application class, you must use the Inherits attribute to specify the name of a code-behind class from which the application class will inherit. Optionally, if you are using an IDE (such as Microsoft Visual Studio 2005) that provides tools for working with code separation source files in code projects, you can add the CodeFile attribute to specify the code-behind source file name.