DropDownList or ListBox

Hi
It is required to provide user interface with either DropDownList or ListBox where the end user can select more than one List Item.
I think using ASP.NET Drop DownList control it is not feasible to provide the functionality where the user can select more than one List Item. I mean to say just ASP.NET controls, not any other controls available in goolgle search. Correct me if i am incorrect.
Removing DropDownList from my control list left with ListBox, yes it is feasible to select more than one ListItem. But the problem is that i need to take user selected number of List Items text from the List Box control and perform search as below.
Select  * from employee
where userId = 123
and (here i like to use ListBox) country = 'UK'
How can i pass user selected List Items from ListBox control where the country name could be single or multiple?
Or can this be achieved easily usi ...