动态更新ModelForm的Meta类

Question

我希望从我的视图中动态更新ModelForm的内联Meta类。虽然此代码似乎更新了Meta类中的排除列表，但as_p()，as_ul()等的输出并不反映更新的Meta排除。

我假设在创建ModelForm时不是在调用as_*()时生成html。有没有办法强制更新HTML？

这是最好的方法吗？我只是假设这个应该工作。

思想？

from django.forms import ModelForm

from testprogram.online_bookings.models import Passenger

class PassengerInfoForm(ModelForm):

    def set_form_excludes(self, exclude_list):
        self.Meta.exclude = excludes_list

    class Meta:
        model = Passenger
        exclude = []

Answer 1

Meta类用于动态构造表单定义 - 因此，当您创建ModelForm实例时，不在排除中的字段已添加为新对象的属性。

执行此操作的常规方法是为每个可能的排除列表提供多个类定义。但是如果你希望表单本身是动态的，你必须动态创建一个类定义。类似的东西：

def get_form(exclude_list):
    class MyForm(ModelForm):
        class Meta:
            model = Passenger
            exclude = exclude_list
    return MyForm

form_class = get_form(('field1', 'field2'))
form = form_class()

更新：我刚刚重访这篇文章，并认为我会发布一些更惯用的方式来处理动态类：

def PassengerForm(exclude_list, *args, **kwargs):
    class MyPassengerForm(ModelForm):
        class Meta:
            model = Passenger
            exclude = exclude_list

        def __init__(self):
            super(MyPassengerForm, self).__init__(*args, **kwargs)

    return MyPassengerForm()

form = PassengerForm(('field1', 'field2'))

Answer 2

另一种方式：

class PassengerInfoForm(ModelForm):
    def __init__(self, *args, **kwargs):
        exclude_list=kwargs.pop('exclude_list', '')

        super(PassengerInfoForm, self).__init__(*args, **kwargs)

        for field in exclude_list:
            del self.fields[field]

    class Meta:
        model = Passenger

form = PassengerInfoForm(exclude_list=['field1', 'field2'])

Answer 3

类似的方法，有些不同的目标（任意模型的通用ModelForm）：

from django.contrib.admin.widgets import AdminDateWidget
from django.forms import ModelForm
from django.db import models

def ModelFormFactory(some_model, *args, **kwargs):
    """
    Create a ModelForm for some_model
    """
    widdict = {}
    # set some widgets for special fields
    for field in some_model._meta.local_fields:
        if type(field) is models.DateField:
            widdict[field.name] = AdminDateWidget()

    class MyModelForm(ModelForm): # I use my personal BaseModelForm as parent
        class Meta:
            model = some_model
            widgets = widdict

    return MyModelForm(*args, **kwargs)

Answer 4

使用modelform_factory（ doc ）：

from django.forms.models import modelform_factory

from testprogram.online_bookings.models import Passenger

exclude = ('field1', 'field2')
CustomForm = modelform_factory(model=Passenger, exclude=exclude)  # generates ModelForm dynamically
custom_form = CustomForm(data=request.POST, ...)  # form instance