If you have an existing page that uses code inline and want to associate a code file with it, do the following:
1. Assuming that name of the page is Foo.aspx, create a new code file named Foo.aspx.vb in the same directory.
2. Change page directive to
3. Close and reopen the solution or Web site.
The code file should now correctly show up in the Solution Explorer as a subnode of the page file.