[英]Django - How to populate manytomany field in forms by previously selected options by users
How can I populate manytomany form field with previous user selected subs.如何使用以前用户选择的子项填充 manytomany 表单字段。
In this code forms render choices with empty checkboxes.在此代码表单中,呈现带有空复选框的选项。 I want checkboxes to show which subscriptions user subscribed to.
我希望复选框显示用户订阅了哪些订阅。
class Subscription(models.Model):
SUBSCRIPTION_TYPES = (
('SUB1', _('sub 1')),
('SUB2', _('sub 2')),
)
subscription_type = models.CharField(choices=SUBSCRIPTION_TYPES, max_length=30, unique=True)
description = models.CharField(max_length=255, blank=True)
class UserSubscription(models.Model):
user = models.OneToOneField(User, on_delete=models.CASCADE)
subscriptions = models.ManyToManyField(Subscription, related_name='subscriptions',
related_query_name='subscriptions')
class SubscriptionForm(forms.ModelForm):
class Meta:
model = UserSubscription
fields = ('subscriptions',)
widgets = {
'subscriptions': forms.CheckboxSelectMultiple(),
}
class SubscriptionFormView(FormView):
template_name = 'profile/subscription.html'
form_class = SubscriptionForm
Please do not create a UserSubscription
, now you defined two junction tables.请不要创建
UserSubscription
,现在你定义了两个结表。 This will result in duplicate data, and will make queries less efficient, and more error-prone logic.这将导致重复数据,并使查询效率降低,并且更容易出错的逻辑。
What you need is a ManyToManyField
from the Subscription
to the User
, so:您需要的是从
Subscription
到User
的ManyToManyField
,因此:
class Subscription(models.Model):
# …
subscribers = models.ManyToManyField(
settings.AUTH_USER_MODEL,
related_name='subscriptions'
)
Then we can define a form to select the Subscription
s:然后我们可以定义一个表单来选择
Subscription
:
from django import forms
class SubscribingForm(forms.Form):
subscriptions = forms.ModelMultipleChoiceField(
queryset=Subscription.objects.all(),
widget=forms.CheckboxSelectMultiple()
)
Then in the view we can handle the form and subscribe the logged in user to all the subscriptions that have been selected:然后在视图中我们可以处理表单并为登录用户订阅所有已选择的订阅:
from django.contrib.auth.mixins import LoginRequiredMixin
from django.shortcuts import redirect
class SubscriptionFormView(LoginRequiredMixin, FormView):
template_name = 'profile/subscription.html'
form_class = SubscribingForm
def get_initial(self):
initial = super().get_initial()
initial['subscriptions'] = self.request.user.subscriptions.all()
return initial
def form_valid(self, form):
subs = form.cleaned_data['subscriptions']
self.request.suer.subscriptions.add(*subs)
return redirect('name-of-some-view')
Note : You can limit views to a class-based view to authenticated users with the
LoginRequiredMixin
mixin [Django-doc] .注意:您可以使用
LoginRequiredMixin
mixin [Django-doc]将基于类的视图的视图限制为经过身份验证的用户。
Note : In case of a successful POST request, you should make a
redirect
[Django-doc] to implement the Post/Redirect/Get pattern [wiki] .注意:如果 POST 请求成功,您应该进行
redirect
[Django-doc]以实现Post/Redirect/Get模式 [wiki] 。 This avoids that you make the same POST request when the user refreshes the browser.这可以避免您在用户刷新浏览器时发出相同的 POST 请求。
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