wxEvent Class Reference

#include <wx/event.h>

Inheritance diagram for wxEvent:

Detailed Description

An event is a structure holding information about an event passed to a callback or member function.

wxEvent used to be a multipurpose event object, and is an abstract base class for other event classes (see below).

For more information about events, see the Events and Event Handling overview.

wxPerl Note: In wxPerl custom event classes should be derived from Wx::PlEvent and Wx::PlCommandEvent.

Library:  wxBase

Category:  Events

See Also

wxCommandEvent, wxMouseEvent

Public Member Functions
	wxEvent (int id=0, wxEventType eventType=wxEVT_NULL)
	Constructor.
virtual wxEvent *	Clone () const =0
	Returns a copy of the event.
wxObject *	GetEventObject () const
	Returns the object (usually a window) associated with the event, if any.
wxEventType	GetEventType () const
	Returns the identifier of the given event type, such as wxEVT_BUTTON.
virtual wxEventCategory	GetEventCategory () const
	Returns a generic category for this event.
int	GetId () const
	Returns the identifier associated with this event, such as a button command id.
wxObject *	GetEventUserData () const
	Return the user data associated with a dynamically connected event handler.
bool	GetSkipped () const
	Returns true if the event handler should be skipped, false otherwise.
long	GetTimestamp () const
	Gets the timestamp for the event.
bool	IsCommandEvent () const
	Returns true if the event is or is derived from wxCommandEvent else it returns false.
void	ResumePropagation (int propagationLevel)
	Sets the propagation level to the given value (for example returned from an earlier call to wxEvent::StopPropagation).
void	SetEventObject (wxObject *object)
	Sets the originating object.
void	SetEventType (wxEventType type)
	Sets the event type.
void	SetId (int id)
	Sets the identifier associated with this event, such as a button command id.
void	SetTimestamp (long timeStamp=0)
	Sets the timestamp for the event.
bool	ShouldPropagate () const
	Test if this event should be propagated or not, i.e. if the propagation level is currently greater than 0.
void	Skip (bool skip=true)
	This method can be used inside an event handler to control whether further event handlers bound to this event will be called after the current one returns.
int	StopPropagation ()
	Stop the event from propagating to its parent window.
Public Member Functions inherited from wxObject
	wxObject ()
	Default ctor; initializes to NULL the internal reference data.
	wxObject (const wxObject &other)
	Copy ctor.
virtual	~wxObject ()
	Destructor.
virtual wxClassInfo *	GetClassInfo () const
	This virtual function is redefined for every class that requires run-time type information, when using the wxDECLARE_CLASS macro (or similar).
wxObjectRefData *	GetRefData () const
	Returns the wxObject::m_refData pointer, i.e. the data referenced by this object.
bool	IsKindOf (const wxClassInfo *info) const
	Determines whether this class is a subclass of (or the same class as) the given class.
bool	IsSameAs (const wxObject &obj) const
	Returns true if this object has the same data pointer as obj.
void	Ref (const wxObject &clone)
	Makes this object refer to the data in clone.
void	SetRefData (wxObjectRefData *data)
	Sets the wxObject::m_refData pointer.
void	UnRef ()
	Decrements the reference count in the associated data, and if it is zero, deletes the data.
void	UnShare ()
	This is the same of AllocExclusive() but this method is public.
void	operator delete (void *buf)
	The delete operator is defined for debugging versions of the library only, when the identifier WXDEBUG is defined.
void *	operator new (size_t size, const wxString &filename=NULL, int lineNum=0)
	The new operator is defined for debugging versions of the library only, when the identifier WXDEBUG is defined.

Protected Attributes
int	m_propagationLevel
	Indicates how many levels the event can propagate.
Protected Attributes inherited from wxObject
wxObjectRefData *	m_refData
	Pointer to an object which is the object's reference-counted data.

Additional Inherited Members
Protected Member Functions inherited from wxObject
void	AllocExclusive ()
	Ensure that this object's data is not shared with any other object.
virtual wxObjectRefData *	CreateRefData () const
	Creates a new instance of the wxObjectRefData-derived class specific to this object and returns it.
virtual wxObjectRefData *	CloneRefData (const wxObjectRefData *data) const
	Creates a new instance of the wxObjectRefData-derived class specific to this object and initializes it copying data.

Constructor & Destructor Documentation

wxEvent::wxEvent	(	int	id = 0,
		wxEventType	eventType = wxEVT_NULL
	)

Constructor.

Notice that events are usually created by wxWidgets itself and creating e.g. a wxPaintEvent in your code and sending it to e.g. a wxTextCtrl will not usually affect it at all as native controls have no specific knowledge about wxWidgets events. However you may construct objects of specific types and pass them to wxEvtHandler::ProcessEvent() if you want to create your own custom control and want to process its events in the same manner as the standard ones.

Also please notice that the order of parameters in this constructor is different from almost all the derived classes which specify the event type as the first argument.

Parameters

id	The identifier of the object (window, timer, ...) which generated this event.
eventType	The unique type of event, e.g. wxEVT_PAINT, wxEVT_SIZE or wxEVT_BUTTON.

Member Function Documentation

virtual wxEvent* wxEvent::Clone ( ) const

pure virtual

Returns a copy of the event.

Any event that is posted to the wxWidgets event system for later action (via wxEvtHandler::AddPendingEvent, wxEvtHandler::QueueEvent or wxPostEvent()) must implement this method.

All wxWidgets events fully implement this method, but any derived events implemented by the user should also implement this method just in case they (or some event derived from them) are ever posted.

All wxWidgets events implement a copy constructor, so the easiest way of implementing the Clone function is to implement a copy constructor for a new event (call it MyEvent) and then define the Clone function like this:

wxEvent *Clone() const { return new MyEvent(*this); }

Implemented in wxThreadEvent, wxRichTextEvent, wxTextUrlEvent, and wxWindowModalDialogEvent.

virtual wxEventCategory wxEvent::GetEventCategory ( ) const

virtual

Returns a generic category for this event.

wxEvent implementation returns wxEVT_CATEGORY_UI by default.

This function is used to selectively process events in wxEventLoopBase::YieldFor.

Reimplemented in wxThreadEvent.

wxObject* wxEvent::GetEventObject

(

)

const

Returns the object (usually a window) associated with the event, if any.

wxEventType wxEvent::GetEventType

(

)

const

Returns the identifier of the given event type, such as wxEVT_BUTTON.

wxObject* wxEvent::GetEventUserData

(

)

const

Return the user data associated with a dynamically connected event handler.

wxEvtHandler::Connect() and wxEvtHandler::Bind() allow associating optional userData pointer with the handler and this method returns the value of this pointer.

The returned pointer is owned by wxWidgets and must not be deleted.

Since

2.9.5

int wxEvent::GetId

(

)

const

Returns the identifier associated with this event, such as a button command id.

bool wxEvent::GetSkipped

(

)

const

Returns true if the event handler should be skipped, false otherwise.

long wxEvent::GetTimestamp

(

)

const

Gets the timestamp for the event.

The timestamp is the time in milliseconds since some fixed moment (not necessarily the standard Unix Epoch, so only differences between the timestamps and not their absolute values usually make sense).

Warning

wxWidgets returns a non-NULL timestamp only for mouse and key events (see wxMouseEvent and wxKeyEvent).

bool wxEvent::IsCommandEvent

(

)

const

Returns true if the event is or is derived from wxCommandEvent else it returns false.

Note

exists only for optimization purposes.

void wxEvent::ResumePropagation

(

int

propagationLevel

)

Sets the propagation level to the given value (for example returned from an earlier call to wxEvent::StopPropagation).

void wxEvent::SetEventObject

(

wxObject *

object

)

Sets the originating object.

void wxEvent::SetEventType

(

wxEventType

type

)

Sets the event type.

void wxEvent::SetId

(

int

id

)

Sets the identifier associated with this event, such as a button command id.

void wxEvent::SetTimestamp

(

long

timeStamp = 0

)

Sets the timestamp for the event.

bool wxEvent::ShouldPropagate

(

)

const

Test if this event should be propagated or not, i.e. if the propagation level is currently greater than 0.

void wxEvent::Skip

(

bool

skip = true

)

This method can be used inside an event handler to control whether further event handlers bound to this event will be called after the current one returns.

Without Skip() (or equivalently if Skip(false) is used), the event will not be processed any more. If Skip(true) is called, the event processing system continues searching for a further handler function for this event, even though it has been processed already in the current handler.

In general, it is recommended to skip all non-command events to allow the default handling to take place. The command events are, however, normally not skipped as usually a single command such as a button click or menu item selection must only be processed by one handler.

int wxEvent::StopPropagation

(

)

Stop the event from propagating to its parent window.

Returns the old propagation level value which may be later passed to ResumePropagation() to allow propagating the event again.

Member Data Documentation

int wxEvent::m_propagationLevel

protected

Indicates how many levels the event can propagate.

This member is protected and should typically only be set in the constructors of the derived classes. It may be temporarily changed by StopPropagation() and ResumePropagation() and tested with ShouldPropagate().

The initial value is set to either wxEVENT_PROPAGATE_NONE (by default) meaning that the event shouldn't be propagated at all or to wxEVENT_PROPAGATE_MAX (for command events) meaning that it should be propagated as much as necessary.

Any positive number means that the event should be propagated but no more than the given number of times. E.g. the propagation level may be set to 1 to propagate the event to its parent only, but not to its grandparent.