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{Library}
  21
  22 \helpref{wxBase}{librarieslist}
  23
  24 \wxheading{See also}
  25
  26 \helpref{wxCommandEvent}{wxcommandevent},\rtfsp
  27 \helpref{wxMouseEvent}{wxmouseevent}
  28
  29 \latexignore{\rtfignore{\wxheading{Members}}}
  30
  31
  32 \membersection{wxEvent::wxEvent}\label{wxeventctor}
  33
  34 \func{}{wxEvent}{\param{int }{id = 0}, \param{wxEventType }{eventType = {\tt wxEVT\_NULL}}}
  35
  36 Constructor. Should not need to be used directly by an application.
  37
  38
  39 \membersection{wxEvent::m\_propagationLevel}\label{wxeventmpropagationlevel}
  40
  41
  42 \member{int}{m\_propagationLevel}
  43
  44 Indicates how many levels the event can propagate. This member is protected and
  45 should typically only be set in the constructors of the derived classes. It
  46 may be temporarily changed by \helpref{StopPropagation}{wxeventstoppropagation}
  47 and \helpref{ResumePropagation}{wxeventresumepropagation} and tested with
  48 \helpref{ShouldPropagate}{wxeventshouldpropagate}.
  49
  50 The initial value is set to either {\tt wxEVENT\_PROPAGATE\_NONE} (by
  51 default) meaning that the event shouldn't be propagated at all or to
  52 {\tt wxEVENT\_PROPAGATE\_MAX} (for command events) meaning that it should be
  53 propagated as much as necessary.
  54
  55 Any positive number means that the event should be propagated but no more than
  56 the given number of times. E.g. the propagation level may be set to $1$ to
  57 propagate the event to its parent only, but not to its grandparent.
  58
  59
  60 \membersection{wxEvent::Clone}\label{wxeventclone}
  61
  62 \constfunc{virtual wxEvent*}{Clone}{\void}
  63
  64 Returns a copy of the event.
  65
  66 Any event that is posted to the wxWidgets event system for later action (via
  67 \helpref{wxEvtHandler::AddPendingEvent}{wxevthandleraddpendingevent} or
  68 \helpref{wxPostEvent}{wxpostevent}) must implement this method. All wxWidgets
  69 events fully implement this method, but any derived events implemented by the
  70 user should also implement this method just in case they (or some event
  71 derived from them) are ever posted.
  72
  73 All wxWidgets events implement a copy constructor, so the easiest way of
  74 implementing the Clone function is to implement a copy constructor for
  75 a new event (call it MyEvent) and then define the Clone function like this:
  76
  77 \begin{verbatim}
  78     wxEvent *Clone(void) const { return new MyEvent(*this); }
  79 \end{verbatim}
  80
  81
  82 \membersection{wxEvent::GetEventObject}\label{wxeventgeteventobject}
  83
  84 \func{wxObject*}{GetEventObject}{\void}
  85
  86 Returns the object (usually a window) associated with the
  87 event, if any.
  88
  89
  90 \membersection{wxEvent::GetEventType}\label{wxeventgeteventtype}
  91
  92 \func{wxEventType}{GetEventType}{\void}
  93
  94 Returns the identifier of the given event type,
  95 such as \texttt{wxEVT\_COMMAND\_BUTTON\_CLICKED}.
  96
  97
  98 \membersection{wxEvent::GetId}\label{wxeventgetid}
  99
 100 \constfunc{int}{GetId}{\void}
 101
 102 Returns the identifier associated with this event, such as a button command id.
 103
 104
 105 \membersection{wxEvent::GetSkipped}\label{wxeventgetskipped}
 106
 107 \constfunc{bool}{GetSkipped}{\void}
 108
 109 Returns true if the event handler should be skipped, false otherwise.
 110
 111
 112 \membersection{wxEvent::GetTimestamp}\label{wxeventgettimestamp}
 113
 114 \func{long}{GetTimestamp}{\void}
 115
 116 Gets the timestamp for the event. The timestamp is the time in milliseconds
 117 since some fixed moment (\emph{not} necessarily the standard Unix Epoch, so
 118 only differences between the timestamps and not their absolute values usually
 119 make sense).
 120
 121
 122 \membersection{wxEvent::IsCommandEvent}\label{wxeventiscommandevent}
 123
 124 \constfunc{bool}{IsCommandEvent}{\void}
 125
 126 Returns true if the event is or is derived from
 127 \helpref{wxCommandEvent}{wxcommandevent} else it returns false.
 128 Note: Exists only for optimization purposes.
 129
 130
 131 \membersection{wxEvent::ResumePropagation}\label{wxeventresumepropagation}
 132
 133 \func{void}{ResumePropagation}{\param{int }{propagationLevel}}
 134
 135 Sets the propagation level to the given value (for example returned from an
 136 earlier call to \helpref{StopPropagation}{wxeventstoppropagation}).
 137
 138
 139 \membersection{wxEvent::SetEventObject}\label{wxeventseteventobject}
 140
 141 \func{void}{SetEventObject}{\param{wxObject* }{object}}
 142
 143 Sets the originating object.
 144
 145
 146 \membersection{wxEvent::SetEventType}\label{wxeventseteventtype}
 147
 148 \func{void}{SetEventType}{\param{wxEventType }{type}}
 149
 150 Sets the event type.
 151
 152
 153 \membersection{wxEvent::SetId}\label{wxeventsetid}
 154
 155 \func{void}{SetId}{\param{int}{ id}}
 156
 157 Sets the identifier associated with this event, such as a button command id.
 158
 159
 160 \membersection{wxEvent::SetTimestamp}\label{wxeventsettimestamp}
 161
 162 \func{void}{SetTimestamp}{\param{long }{timeStamp}}
 163
 164 Sets the timestamp for the event.
 165
 166
 167 \membersection{wxEvent::ShouldPropagate}\label{wxeventshouldpropagate}
 168
 169 \constfunc{bool}{ShouldPropagate}{\void}
 170
 171 Test if this event should be propagated or not, i.e. if the propagation level
 172 is currently greater than $0$.
 173
 174
 175 \membersection{wxEvent::Skip}\label{wxeventskip}
 176
 177 \func{void}{Skip}{\param{bool}{ skip = true}}
 178
 179 This method can be used inside an event handler to control whether further
 180 event handlers bound to this event will be called after the current one
 181 returns. Without Skip() (or equivalently if Skip(false) is used),
 182 the event will not be processed any more. If Skip(true) is called, the event
 183 processing system continues searching for a further handler function for this
 184 event, even though it has been processed already in the current handler.
 185
 186 In general, it is recommended to skip all non-command events to allow the
 187 default handling to take place. The command events are, however, normally not
 188 skipped as usually a single command such as a button click or menu item
 189 selection must only be processed by one handler.
 190
 191
 192 \membersection{wxEvent::StopPropagation}\label{wxeventstoppropagation}
 193
 194 \func{int}{StopPropagation}{\void}
 195
 196 Stop the event from propagating to its parent window.
 197
 198 Returns the old propagation level value which may be later passed to
 199 \helpref{ResumePropagation}{wxeventresumepropagation} to allow propagating the
 200 event again.
 201