An interface for configuring a rule-based list of options.


A rule editor lets the user visually create and configure a list of options that are expressed as a predicate (as described in Predicate Programming Guide). Each row displayed by the rule editor represents a particular path down a tree of choices. The rule editor's delegate provides the tree of choices to be displayed. The rule editor presents those choices to the user as a row of popup buttons, static text fields, and custom views.

NSRuleEditor exposes one binding, rows. You can bind rows to an ordered collection (such as an instance of NSMutableArray). Each object in the collection should have the following properties:


An integer representing the type of the row (NSRuleEditorRowType).


An ordered to-many relation (such as an instance of NSMutableArray) containing the directly nested subrows for the given row.


An ordered to-many relation containing the display values for the row.


An ordered to-many relation containing the criteria for the row.


Configuring the Delegate

var delegate: NSRuleEditorDelegate?

The rule editor’s delegate.

protocol NSRuleEditorDelegate

The NSRuleEditorDelegate protocol defines the optional methods implemented by delegates of NSRuleEditor objects.

Configuring a Rule Editor

var isEditable: Bool

A Boolean value that determines whether the rule editor is editable.

var nestingMode: NSRuleEditor.NestingMode

The rule editor’s nesting mode.

var canRemoveAllRows: Bool

A Boolean value that indicates whether all the rows can be removed.

var rowHeight: CGFloat

The rule editor’s row height.

Working with Formatting

var formattingDictionary: [String : String]?

The formatting dictionary for the rule editor.

var formattingStringsFilename: String?

The name of the rule editor’s strings file.

Providing Data

func reloadCriteria()

Instructs the receiver to refetch criteria from its delegate.

func setCriteria([Any], andDisplayValues: [Any], forRowAt: Int)

Modifies the row at a given index to contain the given items and values.

func criteria(forRow: Int)

Returns the currently chosen items for a given row.

func displayValues(forRow: Int)

Returns the chosen values for a given row.

Obtaining Row Information

var numberOfRows: Int

The number of rows in the rule editor.

func parentRow(forRow: Int)

Returns the index of the parent of a given row.

func row(forDisplayValue: Any)

Returns the index of the row containing a given value.

func rowType(forRow: Int)

Returns the type of a given row.

func subrowIndexes(forRow: Int)

Returns the immediate subrows of a given row.

Working with the Selection

var selectedRowIndexes: IndexSet

The indexes of the rule editor’s selected rows.

func selectRowIndexes(IndexSet, byExtendingSelection: Bool)

Sets in the receiver the indexes of rows that are selected.

Manipulating Rows

func addRow(Any?)

Adds a row to the receiver.

func removeRow(at: Int)

Removes the row at a given index.

func removeRows(at: IndexSet, includeSubrows: Bool)

Removes the rows at given indexes.

Working with Predicates

var predicate: NSPredicate?

The rule editor’s predicate.

func reloadPredicate()

Instructs the receiver to regenerate its predicate by invoking the corresponding delegate method.

func predicate(forRow: Int)

Returns the predicate for a given row.

Supporting Bindings

var rowClass: AnyClass

The class used to create a new row in the “rows” binding.

var rowTypeKeyPath: String

The key path for the row type.

var subrowsKeyPath: String

The key path for the subrows.

var criteriaKeyPath: String

The criteria key path.

var displayValuesKeyPath: String

The display values key path.


enum NSRuleEditor.NestingMode

Specifies a type for nesting modes.

Nesting Modes

These constants specify the nesting mode for the rule editor.

enum NSRuleEditor.RowType

Specifies a type for row types.

Row Types

Specify the type of a rule editor row.

Predicate Part Keys

These strings are used as keys to the dictionary returned from the delegate’s ruleEditor(_:predicatePartsForCriterion:withDisplayValue:inRow:) optional method. To construct a valid predicate, the union of the dictionaries for each item in the row must contain the required parts.


class let rowsDidChangeNotification: NSNotification.Name

This notification is posted to the default notification center whenever the view's rows change.


Inherits From

See Also


class NSButton

A control that defines an area on the screen that can be used to trigger actions.

class NSColorWell

A control that displays a color value and lets the user change that color value.

Date Picker

Display a calendar date and provide controls for editing the date value.

class NSImageView

A display of image data from an NSImage object in a frame.

class NSLevelIndicator

A visual representation of a level or quantity, using discrete values.

Path Control

A display of a file system path or virtual path information.

class NSPopUpButton

A display of a single item from a list of items, and provide an interface for selecting items from the list.

class NSProgressIndicator

An interface that provides visual feedback to the user about the status of an ongoing task.

class NSPredicateEditor

A defined set of rules that allows the editing of predicate objects.

Search Field

Provide a text field that is optimized for text-based search interfaces.

class NSSegmentedControl

Display one or more buttons in a single horizontal group.


Display a range of values from which the user selects a single value.

class NSStepper

An interface with up and down arrow buttons for incrementing or decrementing a value.

Text Field

Provide a simple interface for displaying and editing text, including support for password fields and secure forms of text entry.

Token Field

Provide a text field whose text can be rendered in a visually distinct way so that users can recognize portions more easily.


Provide a space for controls under a window's title bar and above your custom content.

Combo Box

Display a list of values in a pop-up menu that lets the user select a value or type in a custom value.

class NSMatrix

A legacy interface for grouping radio buttons or other types of cells together.

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