Excellent. Thanks for the fix!
On Aug 24, 5:55 am, Russell Keith-Magee <freakboy3...@gmail.com> wrote: > On Mon, Aug 24, 2009 at 6:27 AM, David Haas<david.h.h...@gmail.com> wrote: > > > Hi: > > > Yet again, I've run into a behavior change which seems to be linked to > > svn revision 10190. I've figured out a workaround for my code, but > > I'm wondering if someone could provide some feedback if the change is > > just a definition of previously undefined behavior, or a bug. > > > I've pasted some demo code here:http://dpaste.de/PUvT/ > > > Basically, I have 2 models "A" and "B" with a many-to-many > > relationship through "ABExtra". I have a modelform where I can make > > new instances of "B", with a inline modelformset for adding in > > ABExtras. > > > In r. 10189, the pasted view code works just fine - I create my new > > model B, pass it into my formset forms, then save the formsets. > > > In r.10190, the code throws an integrity error. "abextra.modelb_id > > may not be NULL" > > > I've worked around this bug by doing the following: > > > new_b = form.save() > > for f in formset.forms: > > f.cleaned_data['ma'] = new_b > > nbs= formset.save(commit=false) > > for b in nbs: > > b.ma = new_b > > b.save() > > > But this seems a little redundant. Can someone explain why the > > behavior changed, or maybe a better way for me to save my form & > > formset? > > It isn't so much that the behaviour changed - it's that a behaviour > that previously shouldn't have worked - but did for some reason - now > doesn't work at all :-) > > Your "working" code correctly identifies the fact that the FormSet > instance needs to be bound to an instance of ModelB, but doesn't do so > in the right way. Rather than providing the instance as the 'instance' > argument to the FormSet, you're trying to sneak it into the form data. > > The right way to structure your view is something like the following: > > form = forms.ModelBAddForm(request.POST) > if form.is_valid(): > form_validated = True > new_model_b = form.save(commit=False) > else: > form_validated = False > new_model_b = ModelB() > > formset = MBFormSet(instance=new_model_b, data=request.POST) > if form_validated and formset.is_valid(): > formset.save() > return HttpResponseRedirect('../success') > > That is: > * validate the base form, but don't commit the new object; > * construct a formset instance that uses the constructed, but unsaved > instance; > * validate that both the form and formset are OK; > * save the original object and the formset. > > Yours, > Russ Magee %-) --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to django-users+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~----------~----~----~----~------~----~------~--~---
