Contents Up Previous Next

wxEvent

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 Event handling overview.

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

Derived from

wxObject

Include files

<wx/event.h>

See also

wxCommandEvent, wxMouseEvent

Members

wxEvent::wxEvent
wxEvent::m_propagationLevel
wxEvent::Clone
wxEvent::GetEventObject
wxEvent::GetEventType
wxEvent::GetId
wxEvent::GetSkipped
wxEvent::GetTimestamp
wxEvent::IsCommandEvent
wxEvent::ResumePropagation
wxEvent::SetEventObject
wxEvent::SetEventType
wxEvent::SetId
wxEvent::SetTimestamp
wxEvent::ShouldPropagate
wxEvent::Skip
wxEvent::StopPropagation


wxEvent::wxEvent

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

Constructor. Should not need to be used directly by an application.


wxEvent::m_propagationLevel

int m_propagationLevel

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.


wxEvent::Clone

virtual wxEvent* Clone() const

Returns a copy of the event.

Any event that is posted to the wxWidgets event system for later action (via wxEvtHandler::AddPendingEvent 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(void) const { return new MyEvent(*this); }

wxEvent::GetEventObject

wxObject* GetEventObject()

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


wxEvent::GetEventType

wxEventType GetEventType()

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


wxEvent::GetId

int GetId() const

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


wxEvent::GetSkipped

bool GetSkipped() const

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


wxEvent::GetTimestamp

long GetTimestamp()

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).


wxEvent::IsCommandEvent

bool IsCommandEvent() const

Returns true if the event is or is derived from wxCommandEvent else it returns false. Note: Exists only for optimization purposes.


wxEvent::ResumePropagation

void ResumePropagation(int propagationLevel)

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


wxEvent::SetEventObject

void SetEventObject(wxObject* object)

Sets the originating object.


wxEvent::SetEventType

void SetEventType(wxEventType type)

Sets the event type.


wxEvent::SetId

void SetId(int id)

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


wxEvent::SetTimestamp

void SetTimestamp(long timeStamp)

Sets the timestamp for the event.


wxEvent::ShouldPropagate

bool ShouldPropagate() const

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


wxEvent::Skip

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. 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.


wxEvent::StopPropagation

int 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.