Passing and accessing value in Django form - django

Question

I'm trying to pass info to my form and I have a bit of a struggle with that. My code looks as follows:
views.py
class ObjectUpdateView(UpdateView):
template_name = 'manage/object_form.html'
form_class = ObjectEditForm
def get_success_url(self):
#...
def form_valid(self, form):
return super(ObjectUpdateView, self).form_valid(form)
def get_object(self):
return get_object_or_404(Room, pk=self.kwargs['object_id'])
def get_form_kwargs(self, **kwargs):
objectid = self.kwargs['object_id']
object = Object.objects.get(id = objectid)
container = object.container
kwargs['container_id'] = container.id
return kwargs
forms.py
class ObjectEditForm(forms.ModelForm):
class Meta:
model = Object
fields = ['TestField']
def __init__(self, *args, **kwargs):
super(ObjectEditForm, self).__init__(*args, **kwargs)
self.Container_id = kwargs.pop('container_id')
form_page.html
{{fomr.kwarg.Container_id}}
As you can see I'd like to access Container_id value in my form_page.html. Unfortunately, nothing is there. What I also noticed, that with __init__ I had to add, now values are empty in my form. Before I added __init__ all values were properly passed (well, except Container_id).
Could you recommend how I can pass such value to be accessed in the form template?

Answer 1

You can render this with:
{{ form.Container_id }}
In your form you should first pop the container_id from the kwargs, like:
class ObjectEditForm(forms.ModelForm):
class Meta:
model = Object
fields = ['TestField']
def __init__(self, *args, **kwargs):
# first pop from the kwargs
self.Container_id = kwargs.pop('container_id', None)
super(ObjectEditForm, self).__init__(*args, **kwargs)
Use the context over the form
That being said, it is a bit strange that you pass this to the form, and not add this to the context data. You can simplify your view a lot to:
class ObjectUpdateView(UpdateView):
template_name = 'manage/object_form.html'
pk_url_kwarg = 'object_id'
form_class = ObjectEditForm
def get_success_url(self):
#...
def get_context_data(self, **kwargs):
objectid = self.kwargs['object_id']
object = Object.objects.get(id = objectid)
context = super().get_context_data()
context.update(container_id=object.container_id)
return context
Django automatically fetches a single element based on the pk_url_kwarg [Django-doc]. You only need to set it correctly, so here that is the object_id.
In that case, we can simply render this with:
{{ container_id }}
and you do not need to store this in the form.