My advice is to use custom model form and hide these M2M fields if you are creating a new object. You can overwrite the init method of the form to do this.
On Mon, Sep 12, 2011 at 6:01 PM, Carlos Brum <carlos...@gmail.com> wrote: > Hello guys, > > I have a problem to deal with a field ManyToMany in Django. It is > the following: > > When I try to access a list of relations that is my ManyToMany field > I get an error > > "%ModelName% instance needs to have a primary key value before a many- > to-many relationship Can be used. " > > I need to perform validation "before storing the record in the > database". > As you can see in the "view" code below, I used "save" in the > "ModelForm" with "commit = False" > so would build the ManyToMany relationship in memory. > > This did not work. > > I've tried to find the solution on the internet but found nothing that > work. > > Surely someone has been there. > > Thanks to collaboration. > > ###################################### > # Source > ###################################### > Note: The Model "Group" is the native Django admin > > ###################################### > # Model > ###################################### > > class Application (models.Model): > > . . . > > groups = > models.ManyToManyField (Group related_name = 'application') > > . . . > > eh_valida def (self): > > validating = True > > # ###################################### > # HAVE PROBLEMS HERE. The attribute "self.grupos" is not > filled. It should be a list. > # Error: %ModelForm% instance > # Needs to have a primary key value before the > # Many-to-many relationship Can be used. " > # ###################################### > > meuConjuntoDeGrupos = set (self.grupos) > > # ###################################### > . . . > > return validating > > ###################################### > # ModelForm > ###################################### > AplicacaoForm class (ModelForm): > > class Meta: > model = Application > > > # View > > def adiciona_aplicacao (request, idQuestionario): > > form = AplicacaoForm (request.POST) > > if request.method == 'POST': > > if form.is_valid (): > > form.save (commit = False) > > if form.instance.eh_valida (): > > form.save (commit = True) > HttpResponseRedirect return (reverse (manager)) > # > > . . . > > -- > 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. > > -- eng. Ilian Iliev Web Software Developer Mobile: +359 88 66 08 400 Website: http://ilian.i-n-i.org -- 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.
