ModelMultipleChoiceField django 和调试模式

Question

我正在尝试在我的应用程序中实现 ModelMultipleChoiceField，如下所示：链接

model.py

class Services(models.Model):

    id = models.AutoField(primary_key=True)

    type = models.CharField(max_length=300)

class Professionals_Services(models.Model):

    professional = models.ForeignKey(User, on_delete=models.CASCADE)

    service = models.ForeignKey(Services, on_delete=models.CASCADE)

form.py

class ProfileServicesUpdateForm(forms.ModelForm):

    service = forms.ModelMultipleChoiceField(required=False, queryset=Services.objects.all())

    class Meta:

        model = Professionals_Services

        fields = ['service']

    def clean(self):

        # this condition only if the POST data is cleaned, right?

        cleaned_data = super(ProfileServicesUpdateForm, self).clean()

        print(cleaned_data.get('service'))

view.py

class EditProfileServicesView(CreateView):

    model = Professionals_Services

    form_class = ProfileServicesUpdateForm

    context_object_name = 'services'

    template_name = 'accounts/edit-profile.html'

    @method_decorator(login_required(login_url=reverse_lazy('professionals:login')))

    def dispatch(self, request, *args, **kwargs):

        return super().dispatch(self.request, *args, **kwargs)

    def post(self, request, *args, **kwargs):

        form = self.form_class(data=request.POST)

        if form.is_valid():

            services = form.save(commit=False)

            services.save()

html

<select class="ui search fluid dropdown" multiple="" name="service" id="id_service">

  {% for service in services_list %}

    <option value="{{ service.id }}">{{ service.type }}</option>

  {% endfor %}

</select>

对于开发，我使用 Pycham Professionals（最新版本）和 docker，当我运行应用程序并尝试发布 POST 时，答案是：

Cannot assign "<QuerySet [<Services: Services object (2)>, <Services: Services object (5)>, <Services: Services object (6)>, <Services: Services object (7)>]>": "Professionals_Services.service" must be a "Services" instance.

但是，如果我在调试模式下运行应用程序并在应用程序上设置断点，则if form.is_valid(): 应用程序可以正常工作

那是因为 validate 等于 Unknown not in debug

你知道如何修复吗？

Answer 1

你的service是ForeignKey：    service = models.ForeignKey(Services, on_delete=models.CASCADE)AForeignKey表示您选择单个元素，而不是多个元素。您使用ManyToManyField[Django-doc]选择多个元素：class Professionals_Services(models.Model):    professional = models.ForeignKey(User, on_delete=models.CASCADE)    service = models.ManyToManyField(Service)您也不应该重写该post方法，并且可以使用LoginRequiredMixin[Django-doc]来确保用户已登录：from django.contrib.auth.mixins import LoginRequiredMixinclass EditProfileServicesView(LoginRequiredMixin, CreateView):    login_url = reverse_lazy('professionals:login')    model = Professionals_Services    form_class = ProfileServicesUpdateForm    context_object_name = 'services'    template_name = 'accounts/edit-profile.html'    def form_valid(self, form):        form.instance.user = self.request.user        return super().form_valid(form)在您中，Form您还应该返回清理后的数据：class ProfileServicesUpdateForm(forms.ModelForm):    service = forms.ModelMultipleChoiceField(required=False, queryset=Services.objects.all())    class Meta:        model = Professionals_Services        fields = ['service']    def clean(self):        # this condition only if the POST data is cleaned, right?        cleaned_data = super(ProfileServicesUpdateForm, self).clean()        print(cleaned_data.get('service'))        return cleaned_data注意：通常使用settings.AUTH_USER_MODEL[Django-doc]来引用用户模型比直接使用User模型 [Django-doc]更好。注意：Django 中的模型是用PerlCase编写的，而不是Snake_case，因此您可能需要将模型从 重命名Professionals_Services为ProfessionalService。注意：通常 Django 模型有一个单一的名称，所以Services而不是Service.