Adopted by: NSObject (Informal Protocol)
Declared in: AppKit/NSComboBox.h
The NSComboBoxDataSource category declares the methods that an NSComboBox uses to access the contents of its data source object. The combo box determines how many items to display by sending a numberOfItemsInComboBox: message, and accesses individual values with the comboBox:objectValueForItemAtIndex: method. Incremental searches-performed when a user types into the combo box's text field while the pop-up list is displayed-are performed by sending comboBox:indexOfItemWithStringValue: messages to the combo box's data source.
The NSComboBox treats objects provided by its data source as values to be displayed in the combo box's pop-up list. If these objects aren't of common value classes-such as NSString, NSNumber, and so on-you'll need to create a custom NSFormatter to display them. See the NSFormatter class specification for more information.
When an NSComboBoxDataSource is asked to supply a data item, the NSComboBox that sends the request is provided as a parameter. This allows a single data source object to manage several sets of data, choosing the appropriate set based on the identify of the NSComboBox that sends the message.
- (unsigned int)comboBox:(NSComboBox
*)aComboBox indexOfItemWithStringValue:(NSString
*)aString
- (id)comboBox:(NSComboBox
*)aComboBox objectValueForItemAtIndex:(int)index
- (int)numberOfItemsInComboBox:(NSComboBox
*)aComboBox