Wax: problem subclassing TextBox

alex23 wuwei23 at gmail.com
Wed Oct 18 11:01:13 CEST 2006


Hey everyone,

I've just started looking at Wax and have hit a problem I can't
explain. I want an app to respond to every character input into a
TextBox.

Here's a simple, working example:

+++
from wax import *

class MainFrame(VerticalFrame):
  def Body(self):
    self.search = TextBox(self)
    self.search.OnChar = self.OnChar
    self.AddComponent(self.search, expand='h', border=5)

  def OnChar(self, event):
    print 'OnChar:', event.GetKeyCode()
    event.Skip()

app = Application(MainFrame)
app.Run()
+++

This displays a TextBox and entering "abcd" results in:

  OnChar: 97
  OnChar: 98
  OnChar: 99
  OnChar: 100

Rather than defining the OnChar hook on the main frame, though, it
makes more sense (to me) to be defined on the TextBox itself, so I
tried subclassing it as follows:

+++
class NewTextBox(TextBox):
  def OnChar(self, event):
    print 'on char', event.GetKeyCode()
    event.Skip()

class MainFrame(VerticalFrame):
  def Body(self):
    self.search = NewTextBox(self)
    self.AddComponent(self.search, expand='h', border=5)
+++

With the same input of 'abcd', I get the following:
  on char 97
  on char 97
  on char 98
  on char 98
  on char 99
  on char 99
  on char 100
  on char 100

As I understand it, event.Skip() should propagate the event up the
inheritance chain, but I don't see how that would result in
NewTextBox.OnChar being called _twice_ for each input. Stopping the
event there by removing the event.Skip() does result in only one 'on
char XX' line for each character, but also stops _all_ OnChar actions
for the TextBox - such as updating the value and displaying it - and I
really don't want to have to reimplement the full functionality just to
prevent this.

Is there something glaringly obvious that I'm doing wrong in the above
code?

Thanks for any help...

- alex23




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