django - 通过中间类保存 ManyToMany

Question

我阅读了很多关于这个问题的链接:

How to save a django model with a manyToMany Through relationship, AND regular manyToMany relationships

How to save a django model with a manyToMany Through relationship, AND regular manyToMany relationships

django manytomany through

包括文档: https://docs.djangoproject.com/en/dev/topics/db/models/#extra-fields-on-many-to-many-relationships

但无法通过中介类保存我的 M2M。

我的模型:

class Promotor(PessoaFisica):
    user = models.OneToOneField(User, blank=True, null=True)    


class Setor(models.Model):
    nome = models.CharField(max_length=255)
    promotores = models.ManyToManyField(Promotor, through='Membro', blank=True, null=True)     

    class Meta:
        verbose_name_plural = 'setores'

    def __unicode__(self):
        return "%s" % (self.nome)

class Membro(models.Model):
    promotor = models.ForeignKey(Promotor)
    setor = models.ForeignKey(Setor)
    data_inclusao = models.DateField(auto_now=True)  

保存方法:

def add_setor(request):
    form = SetorForm(request.POST or None)
    if form.is_valid():
        s = form.save()    
        setor = get_object_or_404(Setor, pk = s.id)    
        for promotor_id in request.POST.getlist('promotores'):
            membro = Membro.objects.create(promotor_id=promotor_id, setor_id=setor.id)          
            membro.save()         
        messages.add_message(request, messages.SUCCESS, 'Setor cadastrado com sucesso!')
        return HttpResponseRedirect('/project/setor/index/')
    return render_to_response('project/setor/form.html', locals(), context_instance=RequestContext(request))

错误是:

Cannot set values on a ManyToManyField which specifies an intermediary model.  Use setor.Membro's Manager instead.

如果 save() 方法提交“false”，则“setor”没有“id”放入 Membro 对象。如何通过中间类保存setor？谢谢!

Answer 1

您的表单中有 promotores 字段链接到模型，因此 save() 尝试将其保存到 m2m 字段。您可以使用 commit=False 保存表单，然后手动保存对象(它不会触及 m2m)，然后像现在一样保存 m2m。

附:我猜你应该使用 form.cleaned_data['promotores'] 而不是 request.POST。天知道客户端实际发布了什么。