I followed this article

http://devnet.kentico.com/docs/devguide/index.html?developing_custom_filters.htm

Everything was OK until I select a option from any combo box and then put all the combo box at all(option 0), since then I don't get any value

Example:

1. Enter to the link above
2. don't move any filter
3. click on the button "apply filter"
4. bring all the rows stored in the database(because I didn't set any filter)

to get the error

5. change filter any filter for example "industry" set it to "web design"
6. click on the button "apply filter"
7. I don't get any data maybe because any row has that filter
8. put back the filter "Industry" to "All" (all the combo box to "All")
10. click on the button "apply filter"
11. I don't get data "and that is the error or problem" because since then I don't get the data any more

Thanks