禁止直接分配给多对多集的前端.改用emails_for_help.set() [英] Direct assignment to the forward side of a many-to-many set is prohibited. Use emails_for_help.set() instead

问题描述

我是Django的新手，但未找到有关此问题的任何参考.当我在Django模型(models.py)中使用多对多字段时出现此错误.我猜问题是在表单(forms.py)的view(views.py)中分配m2m字段.

I am new to Django and didn't find any reference regarding this issue. I am getting this error when i use many to many field in Django model (models.py). I guess the issue is assigning m2m field in view(views.py) from form(forms.py).

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

How to assign m2m field in view? (Django version 2.0, python - 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"]

推荐答案

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

You need to get the User object and then add it to emails_for_help field. You can't add an object to ManyToManyField when creating an instance. Have a look at the 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

执行此操作的另一种方法是使用.set().

Another way of doing this is to use .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.

Or you can simply use .add() to add arbitrary number of objects.

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("/")

这篇关于禁止直接分配给多对多集的前端.改用emails_for_help.set()的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！