1. wxNotifyEvent documented

2. wxNotebook event now derives from it under wxGTK too - fixing the
   PAGE_CHANGING event handling bug
3. the controls sample demonstrates PAGE_CHANGING in action


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@2562 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/latex/wx/classes.tex

@@ -122,6 +122,7 @@
 \input node.tex
 \input notebook.tex
 \input noteevt.tex
+\input notifevt.tex
 \input object.tex
 \input outptstr.tex
 \input pagedlg.tex

docs/latex/wx/noteevt.tex

@@ -1,9 +1,24 @@
 \section{\class{wxNotebookEvent}}\label{wxnotebookevent}
 
-This class represents the events generated by a notebook control.
+This class represents the events generated by a notebook control: currently,
+there are two of them. The PAGE\_CHANGING event is sent before the current
+page is changed. It allows to the program to examine the current page (which
+can be retrieved with 
+\helpref{GetOldSelection()}wxnotebookeventgetoldselection}) and to veto the page
+change by calling \helpref{Veto()}{wxnotifyeventveto} if, for example, the
+current values in the controls of the old page are invalid.
+
+The second event - PAGE\_CHANGED - is sent after the page has been changed and
+the program cannot veto it any more, it just informs it about the page change.
+
+To summarize, if the program is interested in validating the page values
+before allowing the user to change it, it should process the PAGE\_CHANGING
+event, otherwise PAGE\_CHANGED is probably enough. In any case, it is probably
+unnecessary to process both events at once.
 
 \wxheading{Derived from}
 
+\helpref{wxNotifyEvent}{wxnotifyevent}\\
 \helpref{wxCommandEvent}{wxcommandevent}\\
 \helpref{wxEvent}{wxevent}\\
 \helpref{wxEvtHandler}{wxevthandler}\\
@@ -37,7 +52,7 @@ Processes a wxEVT\_COMMAND\_NOTEBOOK\_PAGE\_CHANGING event.}
 \func{}{wxNotebookEvent}{\param{wxEventType}{ eventType = wxEVT\_NULL},
  \param{int}{ id = 0}, \param{int}{ sel = -1}, \param{int}{ oldSel = -1}}
 
-Constructor.
+Constructor (used internally by wxWindows only).
 
 \membersection{wxNotebookEvent::GetOldSelection}\label{wxnotebookeventgetoldselection}
 

docs/latex/wx/notifevt.tex

@@ -0,0 +1,52 @@
+\section{\class{wxNotifyEvent}}\label{wxnotifyevent}
+
+This class is not used by the event handlers by itself, but is a base class
+for other event classes (such as \helpref{wxNotebookEvent}{wxnotebookevent}).
+
+It (or an object of a derived class) is sent when the controls state is being
+changed and allows the program to \helpref{Veto()}{wxnotifyeventveto} this
+change if it wants to prevent it from happening.
+
+\wxheading{Derived from}
+
+\helpref{wxCommandEvent}{wxcommandevent}\\
+\helpref{wxEvent}{wxevent}\\
+\helpref{wxEvtHandler}{wxevthandler}\\
+\helpref{wxObject}{wxobject}
+
+\wxheading{Include files}
+
+<wx/event.h>
+
+\wxheading{Event table macros}
+
+None
+
+\wxheading{See also}
+
+\helpref{wxNotebookEvent}{wxnotebookevent}
+
+\latexignore{\rtfignore{\wxheading{Members}}}
+
+\membersection{wxNotifyEvent::wxNotifyEvent}\label{wxnotifyeventconstr}
+
+\func{}{wxNotifyEvent}{\param{wxEventType}{ eventType = wxEVT\_NULL}, \param{int}{ id = 0}}
+
+Constructor (used internally by wxWindows only).
+
+\membersection{wxNotifyEvent::IsAllowed}\label{wxnotifyeventisallowed}
+
+\constfunc{bool}{IsAllowed}{\void}
+
+Returns TRUE if the change is allowed (\helpref{Veto()}{wxnotifyeventveto} 
+hasn't been called) or FALSE otherwise (if it was).
+
+\membersection{wxNotifyEvent::Veto}\label{wxnotifyeventveto}
+
+\func{void}{Veto}{\void}
+
+Prevents the change announced by this event from happening.
+
+It is in general a good idea to notify the user about the reasons for vetoing
+the change because otherwise the applications behaviour (which just refuses to
+do what the user wants) might be quite surprising.