First & last both name should contain same string!?
:)
I think, you want one of them contain specific string
Just use Logical OR
|| instead of
&&
using (var db = new knowitCVdbEntities())
{
var employee = (from p in db.EMPLOYEES
where
p.firstname.Contains(TextBoxSearch.Text) ||
p.lastname.Contains(TextBoxSearch.Text)
select p).ToList();
Happy Coding!
:)