# wx.BookCtrlEvent¶

This class represents the events generated by book controls ( wx.Notebook, wx.Listbook, wx.Choicebook, wx.Treebook, wx.aui.AuiNotebook).

The PAGE_CHANGING events are sent before the current page is changed. It allows the program to examine the current page (which can be retrieved with wx.BookCtrlEvent.GetOldSelection ) and to veto the page change by calling wx.NotifyEvent.Veto if, for example, the current values in the controls of the old page are invalid.

The PAGE_CHANGED events are 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.

## Class Hierarchy¶

Inheritance diagram for class BookCtrlEvent:

## Known Subclasses¶

wx.aui.AuiNotebookEvent

## Methods Summary¶

 __init__ Constructor (used internally by wxWidgets only). GetOldSelection Returns the page that was selected before the change, NOT_FOUND if none was selected. GetSelection Returns the currently selected page, or NOT_FOUND if none was selected. SetOldSelection Sets the id of the page selected before the change. SetSelection Sets the selection member variable.

## Class API¶

class wx.BookCtrlEvent(NotifyEvent)

Possible constructors:

BookCtrlEvent(eventType=wxEVT_NULL, id=0, sel=NOT_FOUND,
oldSel=NOT_FOUND)


This class represents the events generated by book controls (wxNotebook, Listbook, Choicebook, Treebook, AuiNotebook).

### Methods¶

__init__(self, eventType=wxEVT_NULL, id=0, sel=NOT_FOUND, oldSel=NOT_FOUND)

Constructor (used internally by wxWidgets only).

Parameters
• eventType (wx.EventType) –

• id (int) –

• sel (int) –

• oldSel (int) –

GetOldSelection(self)

Returns the page that was selected before the change, NOT_FOUND if none was selected.

Return type

int

GetSelection(self)

Returns the currently selected page, or NOT_FOUND if none was selected.

Return type

int

Note

under Windows, GetSelection will return the same value as GetOldSelection when called from the EVT_BOOKCTRL_PAGE_CHANGING handler and not the page which is going to be selected.

SetOldSelection(self, page)

Sets the id of the page selected before the change.

Parameters

page (int) –

SetSelection(self, page)

Sets the selection member variable.

Parameters

page (int) –

### Properties¶

OldSelection

Selection