wx python 3.0.2 classic SetFocus blows

Question

I had a Progress class that was working fine in 2.8.12.1 unicode:

class Progress(bolt.Progress):
    """Progress as progress dialog."""
    def __init__(self,title=_(u'Progress'),message=u' '*60,parent=None,
            style=wx.PD_APP_MODAL|wx.PD_ELAPSED_TIME|wx.PD_AUTO_HIDE|wx.PD_SMOOTH,
            abort=False, onAbort=None):
        if abort:
            style |= wx.PD_CAN_ABORT
            self.fnAbort = onAbort
        self.dialog = wx.ProgressDialog(title,message,100,parent,style)
        self.dialog.SetFocus() #### line 1295 in the traceback is here ####
        bolt.Progress.__init__(self)
        self.message = message
        self.isDestroyed = False
        self.prevMessage = u''
        self.prevState = -1
        self.prevTime = 0

(bolt.Progress has no wx in it)

In 3.02 however blows with:

Traceback (most recent call last):
    ...
  File "bash\basher\__init__.py", line 2670, in _refresh_installers_if_needed
    with balt.Progress(_(u'Refreshing Installers...'),u'\n'+u' '*60, abort=canCancel) as progress:
  File "bash\balt.py", line 1295, in __init__
    self.dialog.SetFocus()
  File "C:\_\Python27\lib\site-packages\wx-3.0-msw\wx\_core.py", line 10129, in SetFocus
    return _core_.Window_SetFocus(*args, **kwargs)
wx._core.PyAssertionError: C++ assertion "hWnd" failed at ..\..\src\msw\window.cpp(562) in wxWindow::SetFocus(): can't set focus to invalid window

Now can anyone spot what is invalid about this window ? As seen the Progress is instantiated in:

with balt.Progress(_(u'Refreshing Installers...'),u'\n'+u' '*60, abort=canCancel) as progress:

so parent is None - is it because of that ? However why the change in behavior in 3.0.2 ? EDIT: well no - passing a non None parent in makes no difference

Incidentally if I remove the SetFocus call it goes on to blow in another setFocus call later on:

def doProgress(self,state,message):
    if not self.dialog:
        raise StateError(u'Dialog already destroyed.')
    elif (state == 0 or state == 1 or (message != self.prevMessage) or
        (state - self.prevState) > 0.05 or (time.time() - self.prevTime) > 0.5):
        self.dialog.SetFocus() #### blows here, this self.dialog is really, really invalid ####
        if message != self.prevMessage:
            ret = self.dialog.Update(int(state*100),message)
            if not ret[0]:
                if self.onAbort():
                    raise CancelError
        else:
            ret = self.dialog.Update(int(state*100))
            if not ret[0]:
                if self.onAbort():
                    raise CancelError
        self.prevMessage = message
        self.prevState = state
        self.prevTime = time.time()

Not sure if all this hocus pocus is needed or if it could be simplified, but my immediate concern is why the window is invalid.

Answer 1

On Windows the ProgressDialog is now a stock common control (like MessageDialog, FileDialog, etc.) instead of a generic dialog implemented in wx like it used to be. So it is not a real native window any longer but just a wrapper around a platform API. So this means that it has no native window handle, and most non-ProgressDialog-specific APIs like SetFocus will not work.