I did the coding on the chapter as in the book with the file downloads but I keep getting the same error. This concerns with page 261. I keep getting error with the 'objAllCountries' which its typename cannot be found.

I did a side by side comparison with the download files and can't find any other problem. I know that this objectdatasource references to the 'Helpers' class .

Make sure that your namespace in Helpers.cs match. That is probably the source of the problem.