django - How do I filter a model field on a form that is a foreignkey but not the main foreignkey -

i have inlineformset_factory group of shoppinglistitemform

view:

class shoppinglistitemform(modelform):     @property     def __name__(self):         return self.__class__.__name__      def __init__(self, *args, **kwargs):          if kwargs.get('instance'):              thelist = kwargs['instance']             self.fields['category'] = forms.choicefield(choices=[(cat.id, cat.name) cat in listitemcategory.objects.filter(shoppinglist__id=thelist.id)])          return super(shoppinglistitemform, self).__init__(self, *args, **kwargs)        class meta:         model = shoppinglistitem         fields = ('item', 'brand', 'quantity', 'current', 'category', 'size', )   @login_required def shoppinglist(request, shoppinglist_id, pod_id):     profile = request.user.get_profile()     shoppinglist = get_object_or_404(shoppinglist, pk=shoppinglist_id)      listformset = inlineformset_factory(shoppinglist, shoppinglistitem, form=shoppinglistitemform, extra=1, can_delete=true)      myforms = listformset(instance=shoppinglist) 

...this works great, except 'category' foreign key of shoppinglistitem, , need filter 'category' options offered on form related listitemcategory 'shoppinglist'. 'shoppinglist' foreign key of both listitemcategory , shoppinglistitem.

models:

class listitemcategory(models.model):     name = models.charfield(max_length=30, blank=true, null=true)     shoppinglist = models.foreignkey(shoppinglist)  class shoppinglistitem(models.model):     shoppinglist = models.foreignkey(shoppinglist)     category = models.foreignkey(listitemcategory, blank=true, null=true, default = none)     item = models.charfield(max_length=200, blank=true, null=true)  class shoppinglist(models.model):     name = models.charfield(max_length=30, blank=true, null=true, default="pod list") 

...i think there no need pass in 'shoppinglist' argument, passed instance of form, initialization added, rendered template has nothing @ in formset.

any further advice?

your issue you're not "initializing" variable shoppinglist_id in form def init

try this:

class shoppinglistitemform(modelform):     class meta:         model = shoppinglistitem         fields = ('item', 'brand', 'quantity', 'current', 'category', 'size', )      def __init__(self, *args, **kwargs):         shoppinglist_id = kwargs.pop('shoppinglist_id', none)         super(shoppinglistitemform, self).__init__(*args, **kwargs)         self.fields['category'].queryset = listitemcategory.objects.filter(shoppinglist__id=shoppinglist_id) 

and should edit how initialize form:

listformset = inlineformset_factory(shoppinglist, shoppinglistitem, form=shoppinglistitemform(shoppinglist_id=shoppinglist.id), extra=1, can_delete=true) 

the changes made next ones:

1. pass shoppinglist_id kwarg argument

...shoppinglistitemform(shoppinglist_id=shoppinglist.id)

2. get kwarg argument in form

   def __init__(self, *args, **kwargs): shoppinglist_id = kwargs.pop('shoppinglist_id', none)