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.pyclass 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.pyclass 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.pyclass 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 LoginRequiredMixin

class 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。

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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。

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注意：通常 Django 模型有一个单一的名称，所以Services而不是Service.