The DBLookup ListBox and DBLookup ComboBox Components

This pair of components is so similar in nature that it makes sense to discuss them in tandem. DBLookupListBox and DBLookupComboBox are data-aware controls that build their display items lists from either of two sources: The data can come from a lookup field defined in a dataset or from a secondary data source altogether. The controls present the user with a limited list of choices with which to fill the associated dataset field.

Physically, these controls are the same as their non-lookup counterparts discussed in the previous paragraphs. The lookup controls differ in the source for the items contained in the list. They come from external sources, and because of that they offer unlimited flexibility as to the items presented in the list. Only data supplied by the sources can be selected as the value for the underlying field.

194 ■ Part II—The Delphi Database Tools

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