docs/latex/wx/event.tex

   1 \section{\class{wxEvent}}\label{wxevent}
   2
   3 An event is a structure holding information about an event passed to a
   4 callback or member function. {\bf wxEvent} used to be a multipurpose
   5 event object, and is an abstract base class for other event classes (see below).
   6
   7 For more information about events, see the \helpref{Event handling overview}{eventhandlingoverview}.
   8
   9 \perlnote{In wxPerl custom event classes should be derived from
  10 \texttt{Wx::PlEvent} and \texttt{Wx::PlCommandEvent}.}
  11
  12 \wxheading{Derived from}
  13
  14 \helpref{wxObject}{wxobject}
  15
  16 \wxheading{Include files}
  17
  18 <wx/event.h>
  19
  20 \wxheading{See also}
  21
  22 \helpref{wxCommandEvent}{wxcommandevent},\rtfsp
  23 \helpref{wxMouseEvent}{wxmouseevent}
  24
  25 \latexignore{\rtfignore{\wxheading{Members}}}
  26
  27
  28 \membersection{wxEvent::wxEvent}\label{wxeventctor}
  29
  30 \func{}{wxEvent}{\param{int }{id = 0}, \param{wxEventType }{eventType = {\tt wxEVT\_NULL}}}
  31
  32 Constructor. Should not need to be used directly by an application.
  33
  34
  35 \membersection{wxEvent::m\_propagationLevel}\label{wxeventmpropagationlevel}
  36
  37
  38 \member{int}{m\_propagationLevel}
  39
  40 Indicates how many levels the event can propagate. This member is protected and
  41 should typically only be set in the constructors of the derived classes. It
  42 may be temporarily changed by \helpref{StopPropagation}{wxeventstoppropagation}
  43 and \helpref{ResumePropagation}{wxeventresumepropagation} and tested with
  44 \helpref{ShouldPropagate}{wxeventshouldpropagate}.
  45
  46 The initial value is set to either {\tt wxEVENT\_PROPAGATE\_NONE} (by
  47 default) meaning that the event shouldn't be propagated at all or to
  48 {\tt wxEVENT\_PROPAGATE\_MAX} (for command events) meaning that it should be
  49 propagated as much as necessary.
  50
  51 Any positive number means that the event should be propagated but no more than
  52 the given number of times. E.g. the propagation level may be set to $1$ to
  53 propagate the event to its parent only, but not to its grandparent.
  54
  55
  56 \membersection{wxEvent::Clone}\label{wxeventclone}
  57
  58 \constfunc{virtual wxEvent*}{Clone}{\void}
  59
  60 Returns a copy of the event.
  61
  62 Any event that is posted to the wxWidgets event system for later action (via
  63 \helpref{wxEvtHandler::AddPendingEvent}{wxevthandleraddpendingevent} or
  64 \helpref{wxPostEvent}{wxpostevent}) must implement this method. All wxWidgets
  65 events fully implement this method, but any derived events implemented by the
  66 user should also implement this method just in case they (or some event
  67 derived from them) are ever posted.
  68
  69 All wxWidgets events implement a copy constructor, so the easiest way of
  70 implementing the Clone function is to implement a copy constructor for
  71 a new event (call it MyEvent) and then define the Clone function like this:
  72
  73 \begin{verbatim}
  74     wxEvent *Clone(void) const { return new MyEvent(*this); }
  75 \end{verbatim}
  76
  77
  78 \membersection{wxEvent::GetEventObject}\label{wxeventgeteventobject}
  79
  80 \func{wxObject*}{GetEventObject}{\void}
  81
  82 Returns the object (usually a window) associated with the
  83 event, if any.
  84
  85
  86 \membersection{wxEvent::GetEventType}\label{wxeventgeteventtype}
  87
  88 \func{wxEventType}{GetEventType}{\void}
  89
  90 Returns the identifier of the given event type,
  91 such as \texttt{wxEVT\_COMMAND\_BUTTON\_CLICKED}.
  92
  93
  94 \membersection{wxEvent::GetId}\label{wxeventgetid}
  95
  96 \constfunc{int}{GetId}{\void}
  97
  98 Returns the identifier associated with this event, such as a button command id.
  99
 100
 101 \membersection{wxEvent::GetSkipped}\label{wxeventgetskipped}
 102
 103 \constfunc{bool}{GetSkipped}{\void}
 104
 105 Returns true if the event handler should be skipped, false otherwise.
 106
 107
 108 \membersection{wxEvent::GetTimestamp}\label{wxeventgettimestamp}
 109
 110 \func{long}{GetTimestamp}{\void}
 111
 112 Gets the timestamp for the event. The timestamp is the time in milliseconds
 113 since some fixed moment (\emph{not} necessarily the standard Unix Epoch, so
 114 only differences between the timestamps and not their absolute values usually
 115 make sense).
 116
 117
 118 \membersection{wxEvent::IsCommandEvent}\label{wxeventiscommandevent}
 119
 120 \constfunc{bool}{IsCommandEvent}{\void}
 121
 122 Returns true if the event is or is derived from
 123 \helpref{wxCommandEvent}{wxcommandevent} else it returns false.
 124 Note: Exists only for optimization purposes.
 125
 126
 127 \membersection{wxEvent::ResumePropagation}\label{wxeventresumepropagation}
 128
 129 \func{void}{ResumePropagation}{\param{int }{propagationLevel}}
 130
 131 Sets the propagation level to the given value (for example returned from an
 132 earlier call to \helpref{StopPropagation}{wxeventstoppropagation}).
 133
 134
 135 \membersection{wxEvent::SetEventObject}\label{wxeventseteventobject}
 136
 137 \func{void}{SetEventObject}{\param{wxObject* }{object}}
 138
 139 Sets the originating object.
 140
 141
 142 \membersection{wxEvent::SetEventType}\label{wxeventseteventtype}
 143
 144 \func{void}{SetEventType}{\param{wxEventType }{type}}
 145
 146 Sets the event type.
 147
 148
 149 \membersection{wxEvent::SetId}\label{wxeventsetid}
 150
 151 \func{void}{SetId}{\param{int}{ id}}
 152
 153 Sets the identifier associated with this event, such as a button command id.
 154
 155
 156 \membersection{wxEvent::SetTimestamp}\label{wxeventsettimestamp}
 157
 158 \func{void}{SetTimestamp}{\param{long }{timeStamp}}
 159
 160 Sets the timestamp for the event.
 161
 162
 163 \membersection{wxEvent::ShouldPropagate}\label{wxeventshouldpropagate}
 164
 165 \constfunc{bool}{ShouldPropagate}{\void}
 166
 167 Test if this event should be propagated or not, i.e. if the propagation level
 168 is currently greater than $0$.
 169
 170
 171 \membersection{wxEvent::Skip}\label{wxeventskip}
 172
 173 \func{void}{Skip}{\param{bool}{ skip = true}}
 174
 175 This method can be called by an event handler and controls whether additional
 176 event handlers bound to this event will be called after the current event
 177 handler returns. The default behavior is equivalent to calling Skip(false)
 178 (which is, hence, usually unnecessary) and will prevent additional event
 179 handlers from being called and control will be returned to the sender of the
 180 event immediately after the current handler has finished. If Skip(true) is
 181 called, the event processing system continues searching for a handler
 182 function for this event as if the current handler didn't exist.
 183
 184 In general, it is recommended to skip all non-command events to allow the
 185 default handling to take place. The command events are, however, normally not
 186 skipped as usually a single command such as a button click or menu item
 187 selection must only be processed by one handler.
 188
 189
 190 \membersection{wxEvent::StopPropagation}\label{wxeventstoppropagation}
 191
 192 \func{int}{StopPropagation}{\void}
 193
 194 Stop the event from propagating to its parent window.
 195
 196 Returns the old propagation level value which may be later passed to
 197 \helpref{ResumePropagation}{wxeventresumepropagation} to allow propagating the
 198 event again.
 199