\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.

In some rare cases (so far only dragging the items in the tree control) the
event is disabled by default in which case 
\helpref{Allow()}{wxnotifyeventallow} may be called to allow it.

If both \helpref{Allow()}{wxnotifyeventallow} and 
\helpref{Veto()}{wxnotifyeventveto} are called, only the last method called
counts.

\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::Allow}\label{wxnotifyeventallow}

\func{void}{Allow}{\param{bool }{allow = TRUE}}

Allow the action signalled by this event to be carried.

\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.