Django 将表单迁移到modelform

我写了以下表格：

class VoteForm(forms.Form):
    choice = forms.ModelChoiceField(queryset=None, widget=forms.RadioSelect)

    def __init__(self, *args, **kwargs):
        question = kwargs.pop('instance', None)
        super().__init__(*args, **kwargs)

        if question:
            self.fields['choice'].queryset = question.choice_set

class VoteView(generic.UpdateView):
    template_name = 'polls/vote.html'
    model = Question
    form_class = VoteForm

    def get_queryset(self):
        return Question.objects.filter(pub_date__lte=timezone.now()).exclude(choice__isnull=True)

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        # Check duplicate vote cookie
        cookie = self.request.COOKIES.get(cookie_name)
        if has_voted(cookie, self.object.id):
            context['voted'] = True
        return context

    def get_success_url(self):
        return reverse('polls:results', args=(self.object.id,))

    def form_valid(self, form):
        redirect = super().form_valid(form)

        # Set duplicate vote cookie.
        cookie = self.request.COOKIES.get(cookie_name)
        half_year = timedelta(weeks=26)
        expires = datetime.utcnow() + half_year
        if cookie and re.match(cookie_pattern, cookie):
            redirect.set_cookie(cookie_name, "{}-{}".format(cookie, self.object.id), expires=expires)
        else:
            redirect.set_cookie(cookie_name, self.object.id, expires=expires)

        return redirect

问题在于，普通表单不表示对象，也没有像ModelForm那样的save（）方法。但是我不知道如何迁移表单。没有选项或选项集字段：

class VoteForm(forms.ModelForm):
    class Meta:
        Model = Question
        #throws exception
        fields = ('choice',)
        widgets = {
            'choice': forms.RadioSelect()
                   }

编辑： 以下是模型：

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')

class Choice(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)

---

如何将上面的表单复制为modelform？

即使您有modelform，如果需要，也可以定义其他字段。在您的情况下，它将是选择字段，与前面的正常形式相同

然后在Meta中，您将排除问题模型中所有不需要的字段

之后，在init中，您将向choice字段提供所提供实例的选项集

class VoteForm(forms.ModelForm):
    choice = forms.ModelChoiceField(queryset=None, widget=forms.RadioSelect)

    class Meta:
        model = Question
        exclude = ['question_text','pub_date']

    def __init__(self, *args, **kwargs):
        super(VoteForm, self).__init__(*args, **kwargs)
        instance = getattr(self, 'instance', None)
        if instance:
            self.fields['choice'].queryset = instance.choice_set

---

代码是在线编写的，没有经过测试，但我认为应该可以使用。

请展示您的模型。我添加了模型。