如何将数据从ManyToManyField放入MultipleChoiceField中的选择 [英] How to put data from ManyToManyField to choices in MultipleChoiceField

问题描述

我有一个表格:

*# dialogues.forms*

class CreateConferenceForm(forms.Form):
    ...
    participants = forms.MultipleChoiceField(choices=?)
    ...

我需要输入choices参数而不是?"该模型中来自朋友"字段的数据:

And I need to put in choices argument instead of "?" data from friends field in this model:

*# persons.models*

class Person(User):
    ...
    friends = models.ManyToManyField(
        'self',
        related_name='+',
    ) 
    ...

我该怎么办?

推荐答案

如果要使用表单创建会议模型的实例，则应考虑使用

If you're creating an instance of a conference model with your form, you should consider using Django's ModelForm, which is designed to be used in the creation and editing of model instances.

无论哪种情况，您都可以使用 ModelMultipleChoiceField 可以满足您的目的，这只是一个由查询集支持的MultipleChoiceField用于其选择.您可以在标准Form或ModelForm中使用此字段.

In either case, you can use a ModelMultipleChoiceField to serve your purpose, which is simply a MultipleChoiceField backed by a queryset for its choices. You can use this field in either a standard Form or a ModelForm.

要根据请求自定义选择，可以在视图中设置查询集.

To customize the choices based on the request, you can set the queryset in your view.

例如:

forms.py

class CreateConferenceForm(forms.Form):
    # An initial queryset is required, this is overwritten in the view
    participants = forms.ModelMultipleChoiceField(Person.objects.all())

views.py

def new_conference(request):
    data = request.POST if request.method == 'POST' else None

    conference_form = CreateConferenceForm(data=data)
    conference_form.fields['participants'].queryset = my_person.friends.all()

    if data:
        if conference_form.is_valid():
            # etc

    return render...

请注意，对您而言，在表单上调用is_valid之前设置查询集非常重要，因为查询集用于验证，并且在将表单传递给模板之前(因为查询集用于生成)显示的选择.

Note that it is important for you to set the queryset prior to calling is_valid on the form, since the queryset is used in validation, and prior to sending passing the form to a template, since the queryset is used to generate the choices shown.

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