# wx.ModalDialogHook¶

Allows intercepting all modal dialog calls.

This class can be used to hook into normal modal dialog handling for some special needs. One of the most common use cases is for testing: as automatic tests can’t continue if a modal dialog is shown while they run, this class can be used to avoid showing the modal dialogs during unattended execution. wx.ModalDialogHook can also be used for disabling some background operation while a modal dialog is shown.

To install a modal dialog hook, you need to derive your own class from this one and implement its pure virtual Enter method. Then simply create an object of your class and call Register on it to start receiving calls to your overridden Enter (and possibly wx.Exit ) methods:

class MyModalDialogHook(wx.ModalDialogHook):

def __init__(self, parent):

wx.ModalDialogHook.__init__(self, parent)

def Enter(self, dialog):

# Just for demonstration purposes, intercept all uses of
# wx.FileDialog. Notice that self doesn't provide any real
# sandboxing, of course, the program can still read and write
# files by not using wx.FileDialog to ask the user for their
# names.
if isinstance(dialog, wx.FileDialog):

# Skip showing the file dialog entirely.
return wx.ID_CANCEL

self.lastEnter = wx.DateTime.Now()

# Allow the dialog to be shown as usual.
return wx.ID_NONE

def Exit(self, dialog):

# Again, just for demonstration purposes, show how long did
# the user take to dismiss the dialog. Notice that we
# shouldn't use wx.LogMessage() here as self would result in
# another modal dialog call and hence infinite recursion. In
# general, the hooks should be as unintrusive as possible.
wx.LogDebug("%s dialog took %s to be dismissed",
dialog.GetClassInfo().GetClassName(),
(wx.DateTime.Now() - self.lastEnter).Format())

if __name__ == '__main__':

app = wx.App(0)
self.myHook = MyModalDialogHook(None)
self.myHook.Register()
app.MainLoop()


New in version 2.9.5.

## Class Hierarchy¶

Inheritance diagram for class ModalDialogHook:

## Methods Summary¶

 __init__ Default and trivial constructor. Enter Called by wxWidgets before showing any modal dialogs. Exit Called by wxWidgets after dismissing the modal dialog. Register Register this hook as being active. Unregister Unregister this hook.

## Class API¶

class wx.ModalDialogHook(object)

Possible constructors:

ModalDialogHook()


Allows intercepting all modal dialog calls.

### Methods¶

__init__(self)

Default and trivial constructor.

The constructor doesn’t do anything, call Register to make this hook active.

Enter(self, dialog)

Called by wxWidgets before showing any modal dialogs.

Override this to be notified whenever a modal dialog is about to be shown.

If the return value of this method is ID_NONE, the dialog is shown as usual and wx.Exit will be called when it is dismissed. If the return value is anything else, the dialog is not shown at all and its wx.Dialog.ShowModal simply returns with the given result. In this case, wx.Exit won’t be called neither.

Parameters

dialog (wx.Dialog) – The dialog about to be shown, never None.

Return type

int

Returns

wx.ID_NONE to continue with showing the dialog or anything else to skip showing the dialog and just return this value from its ShowModal().

Exit(self, dialog)

Called by wxWidgets after dismissing the modal dialog.

Notice that it won’t be called if Enter hadn’t been called because another modal hook, registered after this one, intercepted the dialog or if our Enter was called but returned a value different from ID_NONE.

Parameters

dialog (wx.Dialog) – The dialog that was shown and dismissed, never None.

Register(self)

Register this hook as being active.

After registering the hook, its Enter and wx.Exit methods will be called whenever a modal dialog is shown.

Notice that the order of registration matters: the last hook registered is called first, and if its Enter returns a value different from ID_NONE, the subsequent hooks are skipped.

It is an error to register the same hook twice.

Unregister(self)

Unregister this hook.

Notice that is done automatically from the destructor, so usually calling this method explicitly is unnecessary.

The hook must be currently registered.