django modelform显示现有实例

Question

I have the following model:

ynChoice = ((None, 'Acknowledgement not required'),
            (True, 'Acknowledgement and consent required'),
            (False, 'Acknowledgement required but consent not required'))

class AbstractForm(models.Model):
    """base class for the below 2 classes"""
    #require users to say yes and no other than acknowledging #null = not required
    yes_no_required = models.NullBooleanField(choices=ynChoice, blank=False)

and I map it to my modelform:

class LiveConsentForm(forms.ModelForm):
    ynChoice = (
                ('', '---------------'),
                (None, 'Acknowledgement not required'),
                (True, 'Acknowledgement and consent required'),
                (False, 'Acknowledgement required but consent not required'),
                )
    yes_no_required = forms.TypedChoiceField(choices=ynChoice,empty_value='')
    class Meta:
        model = ConsentFormTemplate

Here, ConsentFormTemplate is a subclass of AbstractForm . I wrote yes_no_required in the form because the empty value for the nullbooleanfield's formfield will return a None , which I do not want.

Now, when I want instantiate my form to show an existing record, LiveConsentForm(instance=templateInstance) , I run into a problem.

My templateInstance.yes_no_required 's value is None, but when the html is rendered, ------ is selected. (I do not have such trouble when yes_no_required is either True or False )

Need some help here.

Answer 1

ok i've looked at the forms.fields and

turns out that when rendering to html, turns out that None is just treated as '', and empty_value is not taken into consideration here. I'm not sure why @Ignacio Vazquez-Abrams dude took away his answer, so if you can please put it back up again, i'll accept it.