Django inlineformset_factory中的过滤器查询集

Question

我正在尝试使用inlineformset_factory生成一个表单集。我的模型被定义为：

class Measurement(models.Model):
    subject = models.ForeignKey(Subject)
    experiment = models.ForeignKey(Experiment)
    assay = models.ForeignKey(Assay)
    values = models.CommaSeparatedIntegerField(blank=True, null=True)

class Experiment(models.Model):
    date = models.DateField()
    notes = models.TextField(max_length = 500, blank=True)
    subjects= models.ManyToManyField(Subject)

在我看来，我有：

def add_measurement(request, experiment_id):
    experiment = get_object_or_404(Experiment, pk=experiment_id)
    MeasurementFormSet = inlineformset_factory(Experiment, Measurement, extra=10, exclude=('experiment'))
    if request.method == 'POST':
        formset = MeasurementFormSet(request.POST,instance=experiment)
        if formset.is_valid():
            formset.save()
            return HttpResponseRedirect( experiment.get_absolute_url() ) 
    else:
        formset = MeasurementFormSet(instance=experiment)
    return render_to_response("data_entry_form.html", {"formset": formset, "experiment": experiment }, context_instance=RequestContext(request))

但我希望将Measurement.subject字段限制为仅限于Experiment.subjects查询集中定义的主题。我尝试过几种不同的方法来做这件事，但我不太确定实现这一目标的最佳方式是什么。我试图用一个新的查询集来遍历BaseInlineFormset类，但是无法想出如何正确地传递实验参数。

更新的答案(我还包括这里的信息，作为将参数传递给表单集link的一种方式)：

views.py

def add_measurement(request, experiment_id):    
    experiment = get_object_or_404(Experiment, pk=experiment_id)    
    MeasurementFormSet = inlineformset_factory(Experiment, Measurement, extra=10, can_delete=True, form=MeasurementForm)    
    MeasurementFormSet.form = staticmethod(curry(MeasurementForm, experiment=experiment))
    if request.method == 'POST':
        formset = MeasurementFormSet(request.POST)      
        if formset.is_valid():
        formset.save()
        return HttpResponseRedirect( experiment.get_absolute_url() )    
    else:
        formset = MeasurementFormSet()
        return render_to_response("data_entry_form.html", {"formset": formset, "experiment": experiment }, context_instance=RequestContext(request))

forms.py

class MeasurementForm(ModelForm):
    class Meta:
        model = Measurement
    def __init__(self, *args, **kwargs):
        experiment = kwargs.pop('experiment')
        super(MeasurementForm, self).__init__(*args, **kwargs)
        self.fields["subject"].queryset = Subject.objects.filter(experiment=experiment)

Answer 1

(编辑:没有正确读取代码块，这里应该是您的问题的解决方案)：

我相信你需要：http://docs.djangoproject.com/en/dev/ref/forms/fields/#modelchoicefield

Forms.py:

class MeasurementForm(ModelForm):
 subject = forms.ModelChoiceField(queryset = Expirement.objects.all())
 class Meta:
   model = Measurement

Views.py:

inlineformset_factory(
  Experiment, Measurement, extra=10, 
  exclude=('experiment'), form=MeasurementForm
  )

绑定到窗体集是使用form参数完成的。

Answer 2

我也经历过同样的问题(用有限的可能值初始化inlineform)，并且更新的答案非常有效。谢谢你这么说。无论如何，我认为有些事情可以做得更好，但我不知道如何做到这一点。该解决方案的新问题是在每个inlineform中访问数据库:与其在所有相同的字段中使用相同的queryset，不如在这一行中每次重新计算它：

 self.fields["subject"].queryset = Subject.objects.filter(experiment=experiment)

在这个问题上，我说得对吗?还是有一些懒散的-django-魔术背后的引擎盖？如果我是对的，我如何避免对数据库的(可能的上百次)命中？你好，佩德罗