Question

我读了很多关于这个问题的链接：

但是不能通过中间课程来保存我的M2M。

我的模特：

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（）方法有提交＆＃34; false＆＃34;，＆＃34; setor＆＃34;没有＆＃34; id＆＃34;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()会尝试将其保存到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。

P.S。我想你应该使用form.cleaned_data['promotores']而不是request.POST。上帝知道客户实际发布了什么。

Answer 2

用于保存与中间类（通过）的ManyToMany关系的解决方案：

def add_setor(request):
    form = SetorForm(request.POST or None)
    if form.is_valid():     
        setor = Setor.objects.create(nome=form.cleaned_data['nome'])
        for promotor_id in request.POST.getlist('promotores'):   
            m1 = Membro(promotor_id=promotor_id, setor=setor)
            m1.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))

我没有直接使用表单，但提取表单的setor名称然后创建对象setor。使用表单和对象setor中的id的promotores创建Membro对象，最后一个操作是保存Membro对象。问候。

通过中间类保存ManyToMany

2 个答案: