It does depend on how you've bound the data to the combobox, but you're probably looking for the
Selected Value[
^] property,
There are a number of properties that will help you when trying to determine what the user has selected - SelectedIndex, SelectedItem, SelectedText, SelectedValue
Add an event handler to the combobox to trap when the user selects an item & experiement with these properties to view the data associated with them