NSAppleEventDescriptor Class Reference

Inherits from
Conforms to
Framework
/System/Library/Frameworks/Foundation.framework
Availability
Available in OS X v10.0 and later.
Companion guide
Declared in
NSAppleEventDescriptor.h
Related sample code

Overview

An instance of NSAppleEventDescriptor represents a descriptor—the basic building block for Apple events. This class is a wrapper for the underlying Apple event descriptor data type, AEDesc. Scriptable Cocoa applications frequently work with instances of NSAppleEventDescriptor, but should rarely need to work directly with the AEDesc data structure.

A descriptor is a data structure that stores data and an accompanying four-character code. A descriptor can store a value, or it can store a list of other descriptors (which may also be lists). All the information in an Apple event is stored in descriptors and lists of descriptors, and every Apple event is itself a descriptor list that matches certain criteria.

Descriptors can be used to build arbitrarily complex containers, so that one Apple event can represent a script statement such as tell application "TextEdit" to get word 3 of paragraph 6 of document 3.

In working with Apple event descriptors, it can be useful to understand some of the underlying data types. You’ll find terms such as descriptor, descriptor list, Apple event record, and Apple event defined in Building an Apple Event in Apple Events Programming Guide. You’ll also find information on the four-character codes used to identify information within a descriptor. Apple event data types are defined in Apple Event Manager Reference. The values of many four-character codes used by Apple (and in some cases reused by developers) can be found in AppleScript Terminology and Apple Event Codes.

The most common reason to construct an Apple event with an instance of NSAppleEventDescriptor is to supply information in a return Apple event. The most common situation where you might need to extract information from an Apple event (as an instance of NSAppleEventDescriptor) is when an Apple event handler installed by your application is invoked, as described in “Installing an Apple Event Handler” in How Cocoa Applications Handle Apple Events. In addition, if you execute an AppleScript script using the NSAppleScript class, you get an instance of NSAppleEventDescriptor as the return value, from which you can extract any required information.

When you work with an instance of NSAppleEventDescriptor, you can access the underlying descriptor directly, if necessary, with the aeDesc method. Other methods, including descriptorWithDescriptorType:bytes:length: make it possible to create and initialize instances of NSAppleEventDescriptor without creating temporary instances of NSData.

The designated initializer for NSAppleEventDescriptor is initWithAEDescNoCopy:. However, it is unlikely that you will need to create a subclass of NSAppleEventDescriptor.

Cocoa doesn’t currently provide a mechanism for applications to directly send raw Apple events (though compiling and executing an AppleScript script with NSAppleScript may result in Apple events being sent). However, Cocoa applications have full access to the Apple Event Manager C APIs for working with Apple events. So, for example, you might use an instance of NSAppleEventDescriptor to assemble an Apple event and call the Apple Event Manager function AESend to send it.

If you need to send Apple events, or if you need more information on some of the Apple event concepts described here, see Apple Events Programming Guide and Apple Event Manager Reference.

Adopted Protocols

NSCopying

Tasks

Creating and Initializing Descriptors

Getting Information About a Descriptor

Working With List Descriptors

Working With Record Descriptors

Working With Apple Event Descriptors

Class Methods

appleEventWithEventClass:eventID:targetDescriptor:returnID:transactionID:

Creates a descriptor that represents an Apple event, initialized according to the specified information.

+ (NSAppleEventDescriptor *)appleEventWithEventClass:(AEEventClass)eventClass eventID:(AEEventID)eventID targetDescriptor:(NSAppleEventDescriptor *)addressDescriptor returnID:(AEReturnID)returnID transactionID:(AETransactionID)transactionID
Parameters
eventClass

The event class to be set in the returned descriptor.

eventID

The event ID to be set in the returned descriptor.

addressDescriptor

A pointer to a descriptor that identifies the target application for the Apple event. Passing nil results in an Apple event descriptor that has no keyAddressAttr attribute (it is valid for an Apple event to have no target address attribute).

returnID

The return ID to be set in the returned descriptor. If you pass a value of kAutoGenerateReturnID, the Apple Event Manager assigns the created Apple event a return ID that is unique to the current session. If you pass any other value, the Apple Event Manager assigns that value for the ID.

transactionID

The transaction ID to be set in the returned descriptor. A transaction is a sequence of Apple events that are sent back and forth between client and server applications, beginning with the client’s initial request for a service. All Apple events that are part of a transaction must have the same transaction ID. You can specify kAnyTransactionID if the Apple event is not one of a series of interdependent Apple events.

Return Value

A descriptor for an Apple event, initialized according to the specified parameter values, or nil if an error occurs.

Discussion

Constants such as kAutoGenerateReturnID and kAnyTransactionID are defined in AE.framework, a subframework of ApplicationServices.framework.

Availability
  • Available in OS X v10.0 and later.
Related Sample Code
Declared In
NSAppleEventDescriptor.h

descriptorWithBoolean:

Creates a descriptor initialized with type typeBoolean that stores the specified Boolean value.

+ (NSAppleEventDescriptor *)descriptorWithBoolean:(Boolean)boolean
Parameters
boolean

The Boolean value to be set in the returned descriptor.

Return Value

A descriptor with the specified Boolean value, or nil if an error occurs.

Availability
  • Available in OS X v10.2 and later.
Declared In
NSAppleEventDescriptor.h

descriptorWithDescriptorType:bytes:length:

Creates a descriptor initialized with the specified event type that stores the specified data (from a series of bytes).

+ (NSAppleEventDescriptor *)descriptorWithDescriptorType:(DescType)descriptorType bytes:(const void *)bytes length:(NSUInteger)byteCount
Parameters
descriptorType

The descriptor type to be set in the returned descriptor.

bytes

The data, as a sequence of bytes, to be set in the returned descriptor.

byteCount

The length, in bytes, of the data to be set in the returned descriptor.

Return Value

A descriptor with the specified type and data, or nil if an error occurs.

Availability
  • Available in OS X v10.2 and later.
Declared In
NSAppleEventDescriptor.h

descriptorWithDescriptorType:data:

Creates a descriptor initialized with the specified event type that stores the specified data (from an instance of NSData).

+ (NSAppleEventDescriptor *)descriptorWithDescriptorType:(DescType)descriptorType data:(NSData *)data
Parameters
descriptorType

The descriptor type to be set in the returned descriptor.

data

The data, as an instance of NSData, to be set in the returned descriptor.

Return Value

A descriptor with the specified type and data, or nil if an error occurs.

Discussion

You can use this method to create a descriptor that you can build into a complete Apple event by calling methods such as setAttributeDescriptor:forKeyword:, setDescriptor:forKeyword:, and setParamDescriptor:forKeyword:.

Availability
  • Available in OS X v10.0 and later.
Related Sample Code
Declared In
NSAppleEventDescriptor.h

descriptorWithEnumCode:

Creates a descriptor initialized with type typeEnumerated that stores the specified enumerator data type value.

+ (NSAppleEventDescriptor *)descriptorWithEnumCode:(OSType)enumerator
Parameters
enumerator

A type code that identifies the type of enumerated data to be stored in the returned descriptor.

Return Value

A descriptor with the specified enumerator data type value, or nil if an error occurs.

Availability
  • Available in OS X v10.2 and later.
Declared In
NSAppleEventDescriptor.h

descriptorWithInt32:

Creates a descriptor initialized with Apple event type typeSInt32 that stores the specified integer value.

+ (NSAppleEventDescriptor *)descriptorWithInt32:(SInt32)signedInt
Parameters
signedInt

The integer value to be stored in the returned descriptor.

Return Value

A descriptor containing the specified integer value, or nil if an error occurs.

Availability
  • Available in OS X v10.2 and later.
Related Sample Code
Declared In
NSAppleEventDescriptor.h

descriptorWithString:

Creates a descriptor initialized with type typeUnicodeText that stores the text from the specified string.

+ (NSAppleEventDescriptor *)descriptorWithString:(NSString *)string
Parameters
string

A string that specifies the text to be stored in the returned descriptor.

Return Value

A descriptor that contains the text from the specified string, or nil if an error occurs.

Availability
  • Available in OS X v10.2 and later.
Related Sample Code
Declared In
NSAppleEventDescriptor.h

descriptorWithTypeCode:

Creates a descriptor initialized with type typeType that stores the specified type value.

+ (NSAppleEventDescriptor *)descriptorWithTypeCode:(OSType)typeCode
Parameters
typeCode

The type value to be set in the returned descriptor.

Return Value

A descriptor with the specified type, or nil if an error occurs.

Availability
  • Available in OS X v10.2 and later.
Declared In
NSAppleEventDescriptor.h

listDescriptor

Creates and initializes an empty list descriptor.

+ (NSAppleEventDescriptor *)listDescriptor
Return Value

An empty list descriptor, or nil if an error occurs.

Discussion

A list descriptor is a descriptor whose data consists of one or more descriptors. You can add items to the list by calling insertDescriptor:atIndex: or remove them with removeDescriptorAtIndex:.

Invoking this method is equivalent to allocating an instance of NSAppleEventDescriptor and invoking initListDescriptor.

Availability
  • Available in OS X v10.0 and later.
Related Sample Code
Declared In
NSAppleEventDescriptor.h

nullDescriptor

Creates and initializes a descriptor with no parameter or attribute values set.

+ (NSAppleEventDescriptor *)nullDescriptor
Return Value

A descriptor with no parameter or attribute values set, or nil if an error occurs.

Discussion

You don’t typically call this method, as most NSAppleEventDescriptor instance methods can’t be safely called on the returned empty descriptor.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

recordDescriptor

Creates and initializes a descriptor for an Apple event record whose data has yet to be set.

+ (NSAppleEventDescriptor *)recordDescriptor
Return Value

An Apple event descriptor whose data has yet to be set, or nil if an error occurs.

Discussion

An Apple event record is a descriptor whose data is a set of descriptors keyed by four-character codes. You can add information to the descriptor with methods such as setAttributeDescriptor:forKeyword:, setDescriptor:forKeyword:, and setParamDescriptor:forKeyword:.

Invoking this method is equivalent to allocating an instance of NSAppleEventDescriptor and invoking initRecordDescriptor.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

Instance Methods

aeDesc

Returns a pointer to the AEDesc structure that is encapsulated by the receiver, if it has one.

- (const AEDesc *)aeDesc
Return Value

If the receiver has a valid AEDesc structure, returns a pointer to it; otherwise returns nil.

Availability
  • Available in OS X v10.2 and later.
Declared In
NSAppleEventDescriptor.h

attributeDescriptorForKeyword:

Returns a descriptor for the receiver’s Apple event attribute identified by the specified keyword.

- (NSAppleEventDescriptor *)attributeDescriptorForKeyword:(AEKeyword)keyword
Parameters
keyword

A keyword (a four-character code) that identifies the descriptor to obtain.

Return Value

The attribute descriptor for the specified keyword, or nil if an error occurs.

Discussion

The receiver must be an Apple event.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

booleanValue

Returns the contents of the receiver as a Boolean value, coercing (to typeBoolean) if necessary.

- (Boolean)booleanValue
Return Value

The contents of the descriptor, as a Boolean value, or false if an error occurs.

Availability
  • Available in OS X v10.2 and later.
Related Sample Code
Declared In
NSAppleEventDescriptor.h

coerceToDescriptorType:

Returns a descriptor obtained by coercing the receiver to the specified type.

- (NSAppleEventDescriptor *)coerceToDescriptorType:(DescType)descriptorType
Parameters
descriptorType

The descriptor type to coerce the receiver to.

Return Value

A descriptor of the specified type, or nil if an error occurs.

Availability
  • Available in OS X v10.0 and later.
Related Sample Code
Declared In
NSAppleEventDescriptor.h

data

Returns the receiver’s data as an NSData object.

- (NSData *)data
Return Value

An instance of NSData containing the receiver’s data, or nil if an error occurs.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

descriptorAtIndex:

Returns the descriptor at the specified (one-based) position in the receiving descriptor list.

- (NSAppleEventDescriptor *)descriptorAtIndex:(NSInteger)anIndex
Parameters
anIndex

The one-based descriptor list position of the descriptor to return.

Return Value

The descriptor from the specified position (one-based) in the descriptor list, or nil if the specified descriptor cannot be obtained.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

descriptorForKeyword:

Returns the receiver’s descriptor for the specified keyword.

- (NSAppleEventDescriptor *)descriptorForKeyword:(AEKeyword)keyword
Parameters
keyword

A keyword (a four-character code) that identifies the descriptor to obtain.

Return Value

A descriptor for the specified keyword, or nil if an error occurs.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

descriptorType

Returns the descriptor type of the receiver.

- (DescType)descriptorType
Return Value

The descriptor type of the receiver.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

enumCodeValue

Returns the contents of the receiver as an enumeration type, coercing (to typeEnumerated) if necessary.

- (OSType)enumCodeValue
Return Value

The contents of the descriptor, as an enumeration type, or 0 if an error occurs.

Availability
  • Available in OS X v10.2 and later.
Related Sample Code
Declared In
NSAppleEventDescriptor.h

eventClass

Returns the event class for the receiver.

- (AEEventClass)eventClass
Return Value

The event class (a four-character code) for the receiver, or 0 if an error occurs.

Discussion

The receiver must be an Apple event. An Apple event is identified by its event class and event ID, a pair of four-character codes stored as 32-bit integers. For example, most events in the Standard suite have the four-character code 'core' (defined as the constant kAECoreSuite in AE.framework, a subframework of ApplicationServices.framework). For more information on event classes and event IDs, see Building an Apple Event in Apple Events Programming Guide.

Availability
  • Available in OS X v10.0 and later.
Related Sample Code
Declared In
NSAppleEventDescriptor.h

eventID

Returns the event ID for the receiver.

- (AEEventID)eventID
Return Value

The event ID (a four-character code) for the receiver, or 0 if an error occurs.

Discussion

The receiver must be an Apple event. An Apple event is identified by its event class and event ID, a pair of four-character codes stored as 32-bit integers. For example, the open Apple event from the Standard suite has the four-character code 'odoc' (defined as the constant kAEOpen in AE.framework, a subframework of ApplicationServices.framework).

Availability
  • Available in OS X v10.0 and later.
Related Sample Code
Declared In
NSAppleEventDescriptor.h

initListDescriptor

Initializes a newly allocated instance as an empty list descriptor.

- (id)initListDescriptor
Return Value

An empty list descriptor, or nil if an error occurs.

Discussion

You can add items to the empty list descriptor with insertDescriptor:atIndex:. The list indices are one-based.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

initRecordDescriptor

Initializes a newly allocated instance as a descriptor that is an Apple event record.

- (id)initRecordDescriptor
Return Value

The initialized Apple event record, or nil if an error occurs.

Discussion

An Apple event record is a descriptor whose data is a set of descriptors keyed by four-character codes. You can add information to the descriptor with methods such as setAttributeDescriptor:forKeyword:, setDescriptor:forKeyword:, and setParamDescriptor:forKeyword:.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

initWithAEDescNoCopy:

Initializes a newly allocated instance as a descriptor for the specified Carbon AEDesc structure.

- (id)initWithAEDescNoCopy:(const AEDesc *)aeDesc
Parameters
aeDesc

A pointer to the AEDesc structure to associate with the descriptor.

Return Value

An instance of NSAppleEventDescriptor that is associated with the structure pointed to by aeDesc, or nil if an error occurs.

Discussion

The initialized object takes responsibility for calling the AEDisposeDesc function on the AEDesc at object deallocation time. This is the designated initializer for this class.

Availability
  • Available in OS X v10.2 and later.
Declared In
NSAppleEventDescriptor.h

initWithDescriptorType:bytes:length:

Initializes a newly allocated instance as a descriptor with the specified descriptor type and data (from an arbitrary sequence of bytes and a length count).

- (id)initWithDescriptorType:(DescType)descriptorType bytes:(const void *)bytes length:(NSUInteger)byteCount
Parameters
descriptorType

The descriptor type to be set in the returned descriptor.

bytes

The data, as a sequence of bytes, to be set in the returned descriptor.

byteCount

The length, in bytes, of the data to be set in the returned descriptor.

Return Value

An instance of NSAppleEventDescriptor with the specified type and data. Returns nil if an error occurs.

Availability
  • Available in OS X v10.2 and later.
Declared In
NSAppleEventDescriptor.h

initWithDescriptorType:data:

Initializes a newly allocated instance as a descriptor with the specified descriptor type and data (from an instance of NSData).

- (id)initWithDescriptorType:(DescType)descriptorType data:(NSData *)data
Parameters
descriptorType

The descriptor type to be set in the initialized descriptor.

data

The data to be set in the initialized descriptor.

Return Value

An instance of NSAppleEventDescriptor with the specified type and data. Returns nil if an error occurs.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

initWithEventClass:eventID:targetDescriptor:returnID:transactionID:

Initializes a newly allocated instance as a descriptor for an Apple event, initialized with the specified values.

- (id)initWithEventClass:(AEEventClass)eventClass eventID:(AEEventID)eventID targetDescriptor:(NSAppleEventDescriptor *)addressDescriptor returnID:(AEReturnID)returnID transactionID:(AETransactionID)transactionID
Parameters
eventClass

The event class to be set in the returned descriptor.

eventID

The event ID to be set in the returned descriptor.

addressDescriptor

A pointer to a descriptor that identifies the target application for the Apple event. Passing nil results in an Apple event descriptor that has no keyAddressAttr attribute (it is valid for an Apple event to have no target address attribute).

returnID

The return ID to be set in the returned descriptor. If you pass a value of kAutoGenerateReturnID, the Apple Event Manager assigns the created Apple event a return ID that is unique to the current session. If you pass any other value, the Apple Event Manager assigns that value for the ID.

transactionID

The transaction ID to be set in the returned descriptor. A transaction is a sequence of Apple events that are sent back and forth between client and server applications, beginning with the client’s initial request for a service. All Apple events that are part of a transaction must have the same transaction ID. You can specify kAnyTransactionID if the Apple event is not one of a series of interdependent Apple events.

Return Value

The initialized Apple event (an instance of NSAppleEventDescriptor), or nil if an error occurs.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

insertDescriptor:atIndex:

Inserts a descriptor at the specified (one-based) position in the receiving descriptor list, replacing the existing descriptor, if any, at that position.

- (void)insertDescriptor:(NSAppleEventDescriptor *)descriptor atIndex:(NSInteger)anIndex
Parameters
descriptor

The descriptor to insert in the receiver. Specifying an index of 0 or count + 1 causes appending to the end of the list.

anIndex

The one-based descriptor list position at which to insert the descriptor.

Discussion

Because it actually replaces the descriptor, if any, at the specified position, this method might better be called replaceDescriptor:atIndex:. The receiver must be a list descriptor. The indices are one-based. Currently provides no indication if an error occurs.

Availability
  • Available in OS X v10.0 and later.
Related Sample Code
Declared In
NSAppleEventDescriptor.h

int32Value

Returns the contents of the receiver as an integer, coercing (to typeSInt32) if necessary.

- (SInt32)int32Value
Return Value

The contents of the descriptor, as an integer value, or 0 if an error occurs.

Availability
  • Available in OS X v10.2 and later.
Declared In
NSAppleEventDescriptor.h

keywordForDescriptorAtIndex:

Returns the keyword for the descriptor at the specified (one-based) position in the receiver.

- (AEKeyword)keywordForDescriptorAtIndex:(NSInteger)anIndex
Parameters
anIndex

The one-based descriptor list position of the descriptor to get the keyword for.

Return Value

The keyword (a four-character code) for the descriptor at the one-based location specified by anIndex, or 0 if an error occurs.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

numberOfItems

Returns the number of descriptors in the receiver’s descriptor list.

- (NSInteger)numberOfItems
Return Value

The number of descriptors in the receiver’s descriptor list (possibly 0); returns 0 if an error occurs.

Availability
  • Available in OS X v10.0 and later.
Related Sample Code
Declared In
NSAppleEventDescriptor.h

paramDescriptorForKeyword:

Returns a descriptor for the receiver’s Apple event parameter identified by the specified keyword.

- (NSAppleEventDescriptor *)paramDescriptorForKeyword:(AEKeyword)keyword
Parameters
keyword

A keyword (a four-character code) that identifies the parameter descriptor to obtain.

Return Value

A descriptor for the specified keyword, or nil if an error occurs.

Discussion

The receiver must be an Apple event.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

removeDescriptorAtIndex:

Removes the descriptor at the specified (one-based) position in the receiving descriptor list.

- (void)removeDescriptorAtIndex:(NSInteger)anIndex
Parameters
anIndex

The one-based position of the descriptor to remove.

Discussion

The receiver must be a list descriptor. The indices are one-based. Currently provides no indication if an error occurs.

Availability
  • Available in OS X v10.2 and later.
Declared In
NSAppleEventDescriptor.h

removeDescriptorWithKeyword:

Removes the receiver’s descriptor identified by the specified keyword.

- (void)removeDescriptorWithKeyword:(AEKeyword)keyword
Parameters
keyword

A keyword (a four-character code) that identifies the descriptor to remove.

Discussion

The receiver must be an Apple event or Apple event record. Currently provides no indication if an error occurs.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

removeParamDescriptorWithKeyword:

Removes the receiver’s parameter descriptor identified by the specified keyword.

- (void)removeParamDescriptorWithKeyword:(AEKeyword)keyword
Parameters
keyword

A keyword (a four-character code) that identifies the parameter descriptor to remove. Currently provides no indication if an error occurs.

Discussion

The receiver must be an Apple event or Apple event record, both of which can contain parameters.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

returnID

Returns the receiver’s return ID (the ID for a reply Apple event).

- (AEReturnID)returnID
Return Value

The receiver’s return ID (an integer value), or 0 if an error occurs.

Discussion

The receiver must be an Apple event.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

setAttributeDescriptor:forKeyword:

Adds a descriptor to the receiver as an attribute identified by the specified keyword.

- (void)setAttributeDescriptor:(NSAppleEventDescriptor *)descriptor forKeyword:(AEKeyword)keyword
Parameters
descriptor

The attribute descriptor to add to the receiver.

keyword

A keyword (a four-character code) that identifies the attribute descriptor to add. If a descriptor with that keyword already exists in the receiver, it is replaced.

Discussion

The receiver must be an Apple event. Currently provides no indication if an error occurs.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

setDescriptor:forKeyword:

Adds a descriptor, identified by a keyword, to the receiver.

- (void)setDescriptor:(NSAppleEventDescriptor *)descriptor forKeyword:(AEKeyword)keyword
Parameters
descriptor

The descriptor to add to the receiver.

keyword

A keyword (a four-character code) that identifies the descriptor to add. If a descriptor with that keyword already exists in the receiver, it is replaced.

Discussion

The receiver must be an Apple event or Apple event record. Currently provides no indication if an error occurs.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

setParamDescriptor:forKeyword:

Adds a descriptor to the receiver as an Apple event parameter identified by the specified keyword.

- (void)setParamDescriptor:(NSAppleEventDescriptor *)descriptor forKeyword:(AEKeyword)keyword
Parameters
descriptor

The parameter descriptor to add to the receiver.

keyword

A keyword (a four-character code) that identifies the parameter descriptor to add. If a descriptor with that keyword already exists in the receiver, it is replaced.

Discussion

The receiver must be an Apple event or Apple event record, both of which can contain parameters.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

stringValue

Returns the contents of the receiver as a Unicode text string, coercing (to typeUnicodeText) if necessary.

- (NSString *)stringValue
Return Value

The contents of the descriptor, as a string, or nil if an error occurs.

Availability
  • Available in OS X v10.2 and later.
Declared In
NSAppleEventDescriptor.h

transactionID

Returns the receiver’s transaction ID, if any.

- (AETransactionID)transactionID
Return Value

The receiver’s transaction ID (an integer value), or 0 if an error occurs.

Discussion

The receiver must be an Apple event. Currently provides no indication if an error occurs. For more information on transactions, see the description for appleEventWithEventClass:eventID:targetDescriptor:returnID:transactionID:.

Availability
  • Available in OS X v10.0 and later.
Declared In
NSAppleEventDescriptor.h

typeCodeValue

Returns the contents of the receiver as a type, coercing (to typeType) if necessary.

- (OSType)typeCodeValue
Return Value

The contents of the descriptor, as a type, or 0 if an error occurs.

Availability
  • Available in OS X v10.2 and later.
Related Sample Code
Declared In
NSAppleEventDescriptor.h