Django - 问卷 - ModelFormSet - 无法分配

Question

好的，我正在学习使用 Django 创建一个小型问卷的教程。

用户可以创建包含不同选择题的调查。由于它们是多项选择题，因此用户还可以设置问题的选项。

“调查员”然后可以开始调查，选择他或她喜欢的问题并提交表格。

我希望每页只显示一个问题，因此我尝试使用 modelformset_factory 并使用内置分页器实现分页。

表单正确呈现，用户可以提交答案，但是表单在“formset.is_valid()”之前失败，我就是不知道为什么；

/surveys/1/submit/4/处的ValueError

无法分配“'2'”：“Answer.option”必须是“Option”实例。

所以我无法保存整数，并且我不得不将整数与选项模型中的 id 关联起来……但我还无法访问cleaned_data，所以我想我在这里遗漏了一些东西。我是否忘记了表单集中的某些内容？

我已经盯着这个看了一段时间，所以感谢任何帮助。

#查看次数

def submit(request, survey_pk, sub_pk):
    # Let's retrieve the survey which is created by the survey-taker
    try:
        survey = Survey.objects.prefetch_related("question_set__option_set").get(
            pk=survey_pk, is_active=True
        )
    except Survey.DoesNotExist:
        raise Http404() 

    try:
        submission = survey.submission_set.get(pk=sub_pk, is_complete=False)
    except Submission.DoesNotExist:
        raise Http404() 

    # Retrieve all question associated with this survey 
    questions = survey.question_set.all() 
    # Get all related options from the questions
    options = [q.option_set.all() for q in questions]

    form_kwargs = {"empty_permitted": False, "options": options,}
    # Setup a formset utilizing a ModelFormSet
    AnswerFormset = modelformset_factory(
        Answer, 
        form=AnswerModelForm, 
        formset=BaseAnswerFormSet,
        exclude=(), 
        extra=len(questions), 
    )

    if request.method == "POST":
        print("Request.POST", request.POST)
        # This is where the problem starts
        formset = AnswerFormset(request.POST, form_kwargs=form_kwargs)
        print("Formset: ", formset)
        if formset.is_valid():
            print("Formset is valid")
            with transaction.atomic():
                for form in formset:
                    Answer.objects.create(
                        option_id=form.cleaned_data["option"],
                        submission_id=sub_pk,
                    )

                    submission.is_complete = True 
                    submission.save 
                return redirect("survey-thanks", pk=survey_pk)
    else:
        
        formset = AnswerFormset(form_kwargs=form_kwargs)
        print(form_kwargs)

    question_forms = zip(questions, formset)
    return render(
        request,
        "survey/submit.html",
        {
            "survey": survey,
            "question_forms": question_forms,
            "formset": formset
        }
    )

#forms

# Setup a Modelformset
class AnswerModelForm(forms.ModelForm):
    class Meta:
        model = Answer 
        fields = "option",
    
    def __init__(self, *args, **kwargs):
        options = kwargs.pop("options")
        # Options must be a list of Option objects
        choices = {(o.pk, o.text) for o in options}
        super().__init__(*args, **kwargs)
        option_field = forms.ChoiceField(choices=choices, widget=forms.RadioSelect, required=True)
        self.fields["option"] = option_field 


class BaseAnswerFormSet(forms.BaseFormSet):
    def get_form_kwargs(self, index):
        kwargs = super().get_form_kwargs(index)
        kwargs["options"] = kwargs["options"][index]
        return kwargs

#models

class Answer(models.Model):
    """An answer a survey's questions."""

    submission = models.ForeignKey(Submission, on_delete=models.CASCADE)
    option = models.ForeignKey(Option, on_delete=models.CASCADE)

Answer 1

option_id=form.cleaned_data["option"], 

是嫌疑人，它可能需要一个选项实例，即使您试图传递 id。尝试将 option_id 更改为 option__id 并将 form.cleaned_data["option"] 显式设置为 int。另一种方法是手动拉取选项并直接传递：

option = Option.object.get(id=int(form.cleaned_data["option"]))