Django ModelChoiceField 未使用新数据更新

Question

使用 Django 1.7，我有一个 ModelChoiceField，它在基础数据更新时不会更新。要显示新数据行，我需要重新启动网络服务器。

Django 表单、字段、 View :

class JobsModelChoiceField(forms.ModelChoiceField):

    def __init__(self, *args, **kwargs):
        super(JobsModelChoiceField, self).__init__(*args, **kwargs)
        groups = groupby(sorted(kwargs['queryset'], key=attrgetter('company')), attrgetter('company'))
        self.choices = [(company, [(t.id, self.label_from_instance(t)) for t in title])
                        for company, title in groups]

    def label_from_instance(self, job):
        return u'{} {}'.format(job.id, job.title)

class NewApplicationForm(forms.Form):
    id = JobsModelChoiceField(queryset=Job.objects.all(),
                                widget=forms.Select(attrs={'class':'chosen-select'}))
    first_name = forms.CharField(label='First Name')
    last_name = forms.CharField(label='Last Name')
    email = forms.EmailField(label='Email')
    phone_number = forms.CharField(label='Phone Number', max_length=42, required=False)
    resume = forms.FileField()

    def save(self):
        # save data

class NewApplicationView(SuccessMessageMixin, FormView):

    template_name = 'applicants/new_application.html'
    form_class = NewApplicationForm
    success_url = reverse_lazy('applicants:add')
    success_message = "Job Application was created successfully"

    def form_valid(self, form):
        # This method is called when valid form data has been POSTed.
        # It should return an HttpResponse.
        form.save()
        return super(NewApplicationView, self).form_valid(form)

我遇到的问题的一个例子是，如果我在作业表中添加一个新行，那么在我重新启动 Web 服务器之前，该新行不会显示在表单选择字段中。

Answer 1

这是因为您的表单字段是静态填充的，而不是动态填充的(即不是每次实例化您的表单时)。您应该在表单__init__ 方法中指定表单查询集，如下所示:

class NewApplicationForm(forms.Form):
    id = JobsModelChoiceField(queryset=Job.objects.none(), ...)

...


    def __init__(self, *args, **kwargs):
        super(NewApplicationForm, self).__init__(*args, **kwargs)
        self.fields['id'].queryset = Job.objects.all()