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NSComboBoxDataSource Protocol Reference

(informal protocol)

Overview

The NSComboBoxDataSource informal protocol declares the methods that an NSComboBox object uses to access the contents of its data source object.

For more information, see “Providing Data for a Combo Box”.

Tasks

Returning Information About Combo Box Items

• – comboBox:objectValueForItemAtIndex:
• – numberOfItemsInComboBox:

Working with Entered Strings

• – comboBox:completedString:
• – comboBox:indexOfItemWithStringValue:

Instance Methods

comboBox:completedString:

Returns the first item from the pop-up list that starts with the text the user has typed.

- (NSString *)comboBox:(NSComboBox *)aComboBox completedString:(NSString *)uncompletedString

Parameters

aComboBox

The combo box.

uncompletedString

The string to match against items in the combo box's pop-up list. This is text that the user has typed.

Return Value

The first complete string from the items in the combo box's pop-up list that starts with the string in uncompletedString.

Discussion

An NSComboBox object uses this method to perform incremental—or “smart”—searches when the user types into the text field. As the user types in the text field, the receiver uses this method to search for items from the pop-up list that start with what the user has typed. The receiver adds the new text to the end of the field and selects the new text, so when the user types another character, it replaces the new text.

This method is optional. If you don’t implement it, the receiver does not perform incremental searches.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

NSComboBox.h

comboBox:indexOfItemWithStringValue:

Returns the index of the combo box item matching the specified string.

- (NSUInteger)comboBox:(NSComboBox *)aComboBox indexOfItemWithStringValue:(NSString *)aString

Parameters

aComboBox

The combo box.

aString

The string to match against the items in the combo box. If comboBox:completedString: is implemented, this is the string returned by that method. Otherwise, it is the text that the user has typed.

Return Value

The index for the item that matches the specified string, or NSNotFound if no item matches.

Discussion

An NSComboBox object uses this method to synchronize the pop-up list’s selected item with the text field’s contents. This method is optional. If you don’t implement it, the receiver does not synchronize the pop-up list’s selected item with the text field’s contents.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

NSComboBox.h

comboBox:objectValueForItemAtIndex:

Returns the object that corresponds to the item at the specified index in the combo box.

- (id)comboBox:(NSComboBox *)aComboBox objectValueForItemAtIndex:(NSInteger)index

Parameters

aComboBox

The combo box.

index

The index of the item to return.

Return Value

The object corresponding to the specified index number.

Discussion

Your data source must implement this method.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

NSComboBox.h

numberOfItemsInComboBox:

Returns the number of items that the data source manages for the combo box.

- (NSInteger)numberOfItemsInComboBox:(NSComboBox *)aComboBox

Parameters

aComboBox

The combo box.

Return Value

The number of items that the data source object manages for the specified combo box.

Discussion

An NSComboBox object uses this method to determine how many items it should display in its pop-up list. Your data source must implement this method.

Availability

• Available in Mac OS X v10.0 and later.

Declared In

NSComboBox.h

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