django forms - 用于根据输入更改字段类型的重写构造函数

Question

我需要重写表单的构造函数：如果我在输入中有一些值，则某些字段必须是 ChoiceField，否则它们必须是 CharField。这是代码：

class AnagraficaForm(forms.Form):

    usertype = ((1,'Privato'),(0,'Libero professionista/Azienda'))
    nome = forms.CharField(max_length=100)
    cognome = forms.CharField(max_length=100)
    telefono = forms.CharField(max_length=50,required=False)
    email= forms.EmailField(max_length=100,required=False)
    indirizzo = forms.CharField(max_length=100)
    nazione = forms.ChoiceField(choices = util.get_countries_tuple_list())
    provincia = forms.CharField(max_length=100)
    citta = forms.CharField(max_length=100)
    cap = forms.CharField(max_length=10)
    codfisc = ITSocialSecurityNumberField(required=False)
    piva = ITVatNumberField(required=False)
    ragsociale = forms.CharField(max_length=100,required=False)
    is_privato = forms.TypedChoiceField(
        initial=1,
        coerce=lambda x: bool(int(x)),
        choices=usertype,
        #using custom renderer to display radio buttons on the same line
        widget=forms.RadioSelect(renderer=HorizRadioRenderer, attrs={"id":"is_privato"})
    )

    def __init__(self, country_name = 'ITALIA', region_name = 'MILANO', city_name = 'MILANO', zipcode = '', *args, **kwargs):
        if country_name != 'ITALIA':
            print 'in if'
            self.nazione = forms.ChoiceField(choices = util.get_countries_tuple_list())
            self.provincia = forms.CharField(max_length=100, initial = region_name)
            self.citta = forms.CharField(max_length=100, initial = city_name)
            self.cap = forms.CharField(max_length=10, initial = zipcode)
            kw = {'initial':{'nazione': util.get_country_id(country_name)}}
            kw.update(kwargs)
            return super(AnagraficaForm, self).__init__(*args, **kw)
        else:
            print 'in else'
            self.nazione = forms.ChoiceField(choices = util.get_countries_tuple_list())
            self.provincia = forms.ChoiceField(choices = util.get_regions_tuple_list(util.get_country_id(country_name)))
            self.citta = forms.ChoiceField(choices = util.get_cities_tuple_list(util.get_country_id(country_name), util.get_region_code(region_name)))
            self.cap = forms.ChoiceField(choices = util.get_zips_tuple_list(util.get_country_id(country_name), util.get_region_code(region_name), city_name))
            initial = {
                        'nazione' : 'IT',
                        'provincia' : util.get_region_code(region_name),
                        'citta' : util.get_region_from_cityname(city_name),
                        'cap' : util.get_city_id(zipcode)
                      }
            kw = {'initial': initial}
            kw.update(kwargs)
            return super(AnagraficaForm, self).__init__(*args, **kw)

但是这种方式行不通。即使我将之前的字段声明为 CharField，然后在 init 中覆盖它们，它们也不会在模板中呈现（我收到此消息：）。

有什么帮助吗？

谢谢

Answer 1

您应该在创建表单之后操作self.fields[name]，而不是在它之前触摸self.field。例如，而不是：

self.nazione = forms.ChoiceField(choices = util.get_countries_tuple_list())
super(AnagraficaForm, self).__init__(*args, **kw)

应该有（顺便说一句，__init__ 应该什么都不返回）：

super(AnagraficaForm, self).__init__(*args, **kw)
self.fields['nazione'] = forms.ChoiceField(choices = util.get_countries_tuple_list())

或者，如果两个字段的类型相同，只需修改必要的属性：

self.fields['nazione'].choices = util.get_countries_tuple_list()