Django:ModelMultipleChoiceField不选择初始选择

Question

ModelMultipleChoiceField没有选择初始选项,我无法在我的示例中进行以下修复(链接如下):

http://code.djangoproject.com/ticket/5247#comment:6

我的模特和形式:

class Company(models.Model):
    company_name = models.CharField(max_length=200)

class Contact(models.Model):
    company = models.ForeignKey(Company)
    first_name = models.CharField(max_length=100)
    last_name = models.CharField(max_length=100)

class Action(models.Model):
    company = models.ForeignKey(Company, blank=True, null=True)
    from_company = models.ManyToManyField(Contact, verbose_name='Participant(s) from "Company"', blank=True, null=True)

class Action_Form(ModelForm):
    from_company = forms.ModelMultipleChoiceField(queryset=Contact.objects.none(), widget=forms.CheckboxSelectMultiple())
    class Meta:
        model = Action

我做了什么和结果:

>>> contacts_from_company = Contact.objects.filter(company__exact=1) # "1" for test, otherwise a variable
>>> form = Action_Form(initial={'from_company': [o.pk for o in contacts_from_company]}) # as suggested in the fix
>>> print form['from_company']
<ul>
</ul>
>>> print contacts_from_company
[<Contact: test person>, <Contact: another person>]

>>> form2 = Action_Form(initial={'from_company': contacts_from_company})
>>> print form2['from_company']
<ul>
</ul>

>>> form3 = Action_Form(initial={'from_company': Contact.objects.all()})
>>> print form3['from_company']
<ul>
</ul>

我希望它的工作方式:
1.我的视图从request.GET获得"公司"
2.然后它过滤所有"联系人"为该"公司"
3.最后,它创建一个表单并传递这些"联系人"作为"初始= {...}"

两个问题:
1.[尚未回答]如何让ModelMultipleChoiceField获取那些"初始"值？
2. [回答]作为替代方案,我可以将变量传递给Action_Form(ModelForm),以便在我的ModelForm中我可以:

from_company = forms.ModelMultipleChoiceField(queryset=Contact.objects.filter(company__exact=some_id) # where some_id comes from a view

Answer 1

我正在回复1)

1.如何使ModelMultipleChoiceField获取那些"初始"值？

这可以Action_Form __init__使用ModelMultipleChoiceField initial属性在您的方法中完成.

正如它在Django源代码(db/models/fields/related.py)中所述def formfield(self, **kwargs):

        # If initial is passed in, it's a list of related objects, but the
        # MultipleChoiceField takes a list of IDs.

所以你需要给它一个ID列表:

class Action_Form(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(Action_Form, self).__init__(*args, **kwargs)
        self.fields['from_company'].initial = [c.pk for c in Contact.object.filter()]

Answer 2

您需要添加一个__init__方法来Action_Form设置初始值,记住通过super调用__init__基ModelForm类.

class Action_Form(forms.ModelForm):
    def __init__(self, *args, **kwargs):
        super(Action_Form, self).__init__(*args, **kwargs)
        self.fields['from_company'].queryset = Contact.object.filter(...

如果您计划将过滤器参数作为关键字args传递给Action_Form,则需要在调用super之前删除它们:

myfilter = kwargs['myfilter']
del kwargs['myfilter']

或者,可能更好:

myfilter = kwargs.pop('myfilter')

有关更多信息,请参阅Django中指向Dynamic ModelForms的另一个链接.

Answer 3

如果以前的答案不够直截了当,我会再次尝试回答1):

1. 如何让ModelMultipleChoiceField获取那些"初始"值？

您可以Action_Form像原始问题一样离开,只需使用它来准确呈现您想要的内容:

>>> form4 = Action_Form(initial={'from_company': Contact.objects.all().values_list('id',flat=True)})
>>> print form4['from_company']

Answer 4

回答(1)问题!

这不起作用:

self.fields['from_company'].initial = [c.pk for c in Contact.object.filter()]

但这确实有效:

self.initial['from_company'] = [c.pk for c in Contact.object.filter()]