Dropdownlist inside a Listview to Insert and Edit items

Hi,
I have a categories page with a Listview to insert, edit, delete and update. This works fine.

Then i have a subcategories page with a Listview to insert, edit, delete and update the SUBCATEGORIES.
Subcategories have a Foreign key for CATEGORIES.
Id like to put a dropdownlist inside the ITEM, EDITITEM and INSERTITEM templates, to set or to show the value.
How can i do that ?
...