# wx.NotifyEvent¶

This class is not used by the event handlers by itself, but is a base class for other event classes (such as wx.BookCtrlEvent).

It (or an object of a derived class) is sent when the controls state is being changed and allows the program to wx.NotifyEvent.Veto this change if it wants to prevent it from happening.

## Class Hierarchy¶

Inheritance diagram for class NotifyEvent:

## Methods Summary¶

 __init__ Constructor (used internally by wxWidgets only). Allow This is the opposite of Veto : it explicitly allows the event to be processed. IsAllowed Returns True if the change is allowed ( Veto hasn’t been called) or False otherwise (if it was). Veto Prevents the change announced by this event from happening.

## Class API¶

class wx.NotifyEvent(CommandEvent)

Possible constructors:

NotifyEvent(eventType=wxEVT_NULL, id=0)


This class is not used by the event handlers by itself, but is a base class for other event classes (such as BookCtrlEvent).

### Methods¶

__init__(self, eventType=wxEVT_NULL, id=0)

Constructor (used internally by wxWidgets only).

Parameters
• eventType (wx.EventType) –

• id (int) –

Allow(self)

This is the opposite of Veto : it explicitly allows the event to be processed.

For most events it is not necessary to call this method as the events are allowed anyhow but some are forbidden by default (this will be mentioned in the corresponding event description).

IsAllowed(self)

Returns True if the change is allowed ( Veto hasn’t been called) or False otherwise (if it was).

Return type

bool

Veto(self)

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.