python - NoneType' 对象没有属性 'model'

Question

我的一个表单出现此错误，我似乎无法弄清楚问题出在哪里。

11:24:04 web.1  | Internal Server Error: /dash/location/add
11:24:04 web.1  | Traceback (most recent call last):
11:24:04 web.1  |   File "/Library/Python/2.7/site-packages/django/core/handlers/base.py", line 114, in get_response
11:24:04 web.1  |     response = wrapped_callback(request, *callback_args, **callback_kwargs)
11:24:04 web.1  |   File "/Library/Python/2.7/site-packages/django/contrib/auth/decorators.py", line 22, in _wrapped_view
11:24:04 web.1  |     return view_func(request, *args, **kwargs)
11:24:04 web.1  |   File "/Library/Python/2.7/site-packages/django/views/generic/base.py", line 69, in view
11:24:04 web.1  |     return self.dispatch(request, *args, **kwargs)
11:24:04 web.1  |   File "/Library/Python/2.7/site-packages/django/views/generic/base.py", line 87, in dispatch
11:24:04 web.1  |     return handler(request, *args, **kwargs)
11:24:04 web.1  |   File "/Users/nir/dashboard/pinpoint/apps/locationmanager/views.py", line 43, in post
11:24:04 web.1  |     if form.is_valid():
11:24:04 web.1  |   File "/Library/Python/2.7/site-packages/django/forms/forms.py", line 129, in is_valid
11:24:04 web.1  |     return self.is_bound and not bool(self.errors)
11:24:04 web.1  |   File "/Library/Python/2.7/site-packages/django/forms/forms.py", line 121, in errors
11:24:04 web.1  |     self.full_clean()
11:24:04 web.1  |   File "/Library/Python/2.7/site-packages/django/forms/forms.py", line 273, in full_clean
11:24:04 web.1  |     self._clean_fields()
11:24:04 web.1  |   File "/Library/Python/2.7/site-packages/django/forms/forms.py", line 288, in _clean_fields
11:24:04 web.1  |     value = field.clean(value)
11:24:04 web.1  |   File "/Library/Python/2.7/site-packages/django/forms/fields.py", line 148, in clean
11:24:04 web.1  |     value = self.to_python(value)
11:24:04 web.1  |   File "/Library/Python/2.7/site-packages/django/forms/models.py", line 1136, in to_python
11:24:04 web.1  |     except (ValueError, self.queryset.model.DoesNotExist):
11:24:04 web.1  | AttributeError: 'NoneType' object has no attribute 'model'

这是错误发生的 View :

class AddLocation(View):

    template_name = "dash/Addlocation.html"
    form = locationForm()
    def get(self, request, *args, **kwargs):
        user = User.objects.get(username=request.user.username)
        self.form.fields['region_name'].queryset = Region.objects.filter(location__manager=user)
        return render(request, self.template_name, {'form': self.form})

    def post(self, request, *args, **kwargs):
        form = locationForm(request.POST)
        if form.is_valid():
            region_obj, _created = Region.objects.get_or_create(name=form.cleaned_data['region_name'])
            form.cleaned_data['region_name'] = region_obj
            user = User.objects.get(username=request.user.username)
            location = Location(
                region_obj,
                user,name = form.cleaned_data['name'],
                street_address = form.cleaned_data['street_address'],
                city = form.cleaned_data['city'],
                zip_code = form.cleaned_data['zip_code']
            )
            location.save()

            return redirect(reverse('location_manager'))
        else:
            form = locationForm(request.POST)
            return render(request, self.template_name, {'form': form})

具体来说，问题似乎是在尝试验证 if form.is_valid():

时出现的

如果需要，我可以发布更多信息，但我真的不知道这个错误是什么意思。有人可以阐明这一点吗？

编辑:这是表格本身

from django import forms


    class locationForm(forms.Form):
        region_name = forms.ModelChoiceField(queryset=None, label="Region Name")
        location_name = forms.CharField()
        street_address = forms.CharField()
        city = forms.CharField()
        zip_code = forms.CharField()

Answer 1

您已明确将 region_name 的查询集定义为 None。那是无效的:您需要一个查询集。您确实在 View 的 get 方法中正确分配了一个查询集，但在 post 中却没有，因此当涉及到在 post 上验证表单时，它当然会失败。

与其在 View 中执行此操作，不如在调用 super 之后重写表单的 __init__ 方法并在那里分配查询集。