How to add a "Select All" entry to a Dropdownlist tied to SQLDataSource?

Question

I hvae a dropdownlist tied to a SQLDataSource that returns a list of Categories. Since this is used as part of a search function, how do I add a "Select All" category and ensure that such a selection queries all categories?

Thanks much!!

Answer 1

I sometimes use sql for this:

select value, description from reference_table
union
select -1, 'Select all'
Order by 2

There is also the way where you add the item in the markup, then set the AppendDataBoundItems="true"

Also, see this similar question and answer