akjasim / cb_dj_dependent_dropdown Goto Github PK

Some people may encounter the error of 'NoneType' object has no attribute 'city_set' if you implement this to a profile system or any other similar model. My way around to fix it was :

   if 'country' in self.data:
        try:
            country_id = int(self.data.get('country'))
            self.fields['city'].queryset = City.objects.filter(country_id=country_id).order_by('name')
        except (ValueError, TypeError):
            pass  # invalid input from the client; ignore and fallback to empty City queryset
    elif self.instance.pk:
          try:
              self.fields['city'].queryset = self.instance.country.city_set.order_by('name')
          else:
              pass

Is there a better way to do that because if you look at the steps and start imagining a bigger project, the coding style wouldn't be pleasing at all.
for one dropdown menu, you had to do a lot of things, imagine if you have 10s of them.
please if there is a better way to deal with it, share.

Thanks a lot for the wonderful lesson, but it didn't work with the update.
if I want to update, the chain dropdown shows all the cities regardless of the country, even though in the elif self.data.instance.pk is mentioned, and I think this is related to update. I could be wrong, but it didn't work with update in my case.