Unfortunately, the dropdownlist datatextfield only accepts one fieldname as a parameter, when accessing a database to fill the dropdownlist. To get around this, if you need, say, a first name AND a last name to appear, is to take care of this in the SQL statement a little something like this:
“Select FirstName + ‘ ‘ + LastName as fullname from Employees”
then use ‘fullname’ as the datatextfield for the dropdownlist