禁止直接分配给多对多集的正面。改用emails_for_help.set() - python

我是Django的新手,但未找到有关此问题的任何参考。我在Django模型(models.py)中使用多对多字段时遇到此错误。我想问题是在表单(views.py)的view(forms.py)中分配m2m字段。

如何在视图中分配m2m字段?
(Django version 2.0python - 3.5)

models.py

class User(AbstractUser):
 username=models.CharField(max_length=20)
 email = models.EmailField(_('email address'), unique=True)


class Setupuser(models.Model):
 organization=models.CharField(max_length=200,blank=False,null=True)
 emails_for_help = models.ManyToManyField(User)

views.py

class Set_user(FormView):
 template_name="pkm_templates/set_up_user.html"
 form_class = Set_User_Form
 success_url = '/thanks/'

 def form_valid(self, form):
    org = form.cleaned_data.get('organization')
    emails = form.cleaned_data.get("emails_for_help")
    instance = Setupuser(organization=org,emails_for_help=emails)
    instance.save()
    return redirect("/")

forms.py

class Set_User_Form(ModelForm):
  emails_for_help = forms.ModelMultipleChoiceField(
    queryset=User.objects.all(),
    widget=forms.CheckboxSelectMultiple
  )

  class Meta:
    model = Setupuser
    fields = ["organization","emails_for_help"]

参考方案

您需要获取User对象,然后将其添加到emails_for_help字段。创建实例时,不能将对象添加到ManyToManyField中。看看doc。

class Set_user(FormView):
    template_name="pkm_templates/set_up_user.html"
    form_class = Set_User_Form
    success_url = '/thanks/'

    def form_valid(self, form):
        org = form.cleaned_data.get('organization')
        emails = form.cleaned_data.get("share_email_with")

        users = User.objects.filter(email__in=emails)
        instance = Setupuser.objects.create(organization=org)

        for user in users:
            instance.emails_for_help.add(user)

        return redirect("/")

编辑

另一种方法是使用.set()

class Set_user(FormView):
    template_name="pkm_templates/set_up_user.html"
    form_class = Set_User_Form
    success_url = '/thanks/'

    def form_valid(self, form):
        org = form.cleaned_data.get('organization')
        emails = form.cleaned_data.get("share_email_with")

        users = User.objects.filter(email__in=emails)
        instance = Setupuser.objects.create(organization=org)

        instance.emails_for_help.set(users)

        return redirect("/")

或者,您可以简单地使用.add()添加任意数量的对象。

class Set_user(FormView):
    template_name="pkm_templates/set_up_user.html"
    form_class = Set_User_Form
    success_url = '/thanks/'

    def form_valid(self, form):
        org = form.cleaned_data.get('organization')
        emails = form.cleaned_data.get("share_email_with")

        users = User.objects.filter(email__in=emails)
        instance = Setupuser.objects.create(organization=org)

        instance.emails_for_help.add(*users)

        return redirect("/")

45码