A DataView provides a view into a data source. For example, a program can use one or more DataViews to select different records from a DataTable in a DataSet. Program ContactsLetterLists, shown in Figure 8.15, uses a DataView object to make selecting a subset of the records in a DataSet relatively easy. When you select a letter from the ComboBox on the left, the ListBox displays the records that begin with that letter. If you select the ComboBox’s special entry <New>, the ListBox displays any new records you have just created. Finally, if you select the <All> item, the ListBox shows all the records in the database.
Figure 8.15. Program ContactsLetterLists uses a TreeView control for navigation.
To build this program, open the ContactsListCombined ...