Classes: \helpref{wxEvtHandler}{wxevthandler}, \helpref{wxWindow}{wxwindow}, \helpref{wxEvent}{wxevent}
-\subsection{Introduction}
+\subsection{Introduction}\label{eventintroduction}
-Before version 2.0 of wxWindows, events were handled by the application
+Before version 2.0 of wxWidgets, events were handled by the application
either by supplying callback functions, or by overriding virtual member
functions such as {\bf OnSize}.
-From wxWindows 2.0, {\it event tables} are used instead, with a few exceptions.
+From wxWidgets 2.0, {\it event tables} are used instead, with a few exceptions.
-An event table is placed in an implementation file to tell wxWindows how to map
+An event table is placed in an implementation file to tell wxWidgets how to map
events to member functions. These member functions are not virtual functions, but
they are all similar in form: they take a single wxEvent-derived argument, and have a void return
type.
\subsection{How events are processed}\label{eventprocessing}
-When an event is received from the windowing system, wxWindows calls
+When an event is received from the windowing system, wxWidgets calls
\helpref{wxEvtHandler::ProcessEvent}{wxevthandlerprocessevent} on the first
event handler object belonging to the window generating the event.
-It may be noted that wxWindows' event processing system implements something
+It may be noted that wxWidgets' event processing system implements something
very close to virtual methods in normal C++, i.e. it is possible to alter
the behaviour of a class by overriding its event handling functions. In
many cases this works even for changing the behaviour of native controls.
if ( isalpha( event.KeyCode() ) )
{
// key code is within legal range. we call event.Skip() so the
- // event can be processed either in the base wxWindows class
+ // event can be processed either in the base wxWidgets class
// or the native control.
event.Skip();
\end{enumerate}
{\bf Pay close attention to Step 5.} People often overlook or get
-confused by this powerful feature of the wxWindows event processing
+confused by this powerful feature of the wxWidgets event processing
system. To put it a different way, events set to propagate
(\helpref{See: wxEvent::ShouldPropagate}{wxeventshouldpropagate})
(most likely derived either directly or indirectly from wxCommandEvent)
doesn't call \helpref{event.Skip()}{wxeventskip}.
Finally, there is another additional complication (which, in fact, simplifies
-life of wxWindows programmers significantly): when propagating the command
+life of wxWidgets programmers significantly): when propagating the command
events upwards to the parent window, the event propagation stops when it
reaches the parent dialog, if any. This means that you don't risk to get
unexpected events from the dialog controls (which might be left unprocessed by
and their parent-child relation are well understood by the programmer while it
may be very difficult, if not impossible, to track down all the dialogs which
may be popped up in a complex program (remember that some are created
-automatically by wxWindows). If you need to specify a different behaviour for
+automatically by wxWidgets). If you need to specify a different behaviour for
some reason, you can use
\helpref{SetExtraStyle(wxWS\_EX\_BLOCK\_EVENTS)}{wxwindowsetextrastyle}
explicitly to prevent the events from being propagated beyond the given window
instead of using the slower run-time type system.
As mentioned above, only command events are recursively applied to the parents event
-handler in the libary itself. As this quite often causes confusion for users,
+handler in the library itself. As this quite often causes confusion for users,
here is a list of system events which will NOT get sent to the parent's event handler:
\begin{twocollist}\itemsep=0pt
\twocolitem{\helpref{wxMoveEvent}{wxmoveevent}}{A move event}
\twocolitem{\helpref{wxPaintEvent}{wxpaintevent}}{A paint event}
\twocolitem{\helpref{wxQueryLayoutInfoEvent}{wxquerylayoutinfoevent}}{Used to query layout information}
+\twocolitem{\helpref{wxSetCursorEvent}{wxsetcursorevent}}{Used for special cursor processing based on current mouse position}
\twocolitem{\helpref{wxSizeEvent}{wxsizeevent}}{A size event}
\twocolitem{\helpref{wxScrollWinEvent}{wxscrollwinevent}}{A scroll event sent by a scrolled window (not a scroll bar)}
\twocolitem{\helpref{wxSysColourChangedEvent}{wxsyscolourchangedevent}}{A system colour change event}
% requests, so no extra coding is required to support them in your menus and
% toolbars.
-\subsection{Pluggable event handlers}
+\subsection{Pluggable event handlers}\label{pluggablehandlers}
In fact, you don't have to derive a new class from a window class
if you don't want to. You can derive a new class from wxEvtHandler instead,
long as you don't have several within the same dialog.
If you pass {\tt wxID\_ANY} to a window constructor, an identifier will be
-generated for you automatically by wxWindows. This is useful when you don't
+generated for you automatically by wxWidgets. This is useful when you don't
care about the exact identifier either because you're not going to process the
events from the control being created at all or because you process the events
from all controls in one place (in which case you should specify {\tt wxID\_ANY}
\twocolitem{\helpref{wxPaintEvent}{wxpaintevent}}{The EVT\_PAINT macro is used to handle window paint requests.}
\twocolitem{\helpref{wxScrollEvent}{wxscrollevent}}{These macros are used to handle scroll events from
\helpref{wxScrollBar}{wxscrollbar}, \helpref{wxSlider}{wxslider},and \helpref{wxSpinButton}{wxspinbutton}.}
+\twocolitem{\helpref{wxSetCursorEvent}{wxsetcursorevent}}{The EVT\_SET\_CURSOR macro is used for special cursor processing.}
\twocolitem{\helpref{wxSizeEvent}{wxsizeevent}}{The EVT\_SIZE macro is used to handle a window resize.}
\twocolitem{\helpref{wxSplitterEvent}{wxsplitterevent}}{The EVT\_SPLITTER\_SASH\_POS\_CHANGED, EVT\_SPLITTER\_UNSPLIT
and EVT\_SPLITTER\_DCLICK macros are used to handle the various splitter window events.}
projects / wxWidgets.git / blobdiff