在 Django ModelForm 中添加和初始化自定义字段

Question

我觉得我错过了一些非常基本的观点，但无法解决这个问题。
假设我有这样的模型：

class Person(models.Model):
    first_name = models.CharField(max_length=256, blank=True)
    # this is weird field, but needed for my usecase
    last_name = models.WeirdCustomField(max_length=256, blank=True)

还有一个表格，我想定制一下（cmets）：

class PersonForm(forms.ModelForm):

    class Meta:
        model = Address
        # I want to override 'last_name' field, so exclude it here
        exclude = ['last_name']

    # And add additional field
    my_field = ChoiceField(choices=list_of_choicec)
    last_name = forms.CharField()

    def __init__(self, *args, **kwargs):
        last_name = kwargs.pop('last_name', None)
        my_field = kwargs.pop('my_field', None)
        super(PersonForm, self).__init__(*args, **kwargs)
        self.fields['last_name'] = last_name
        self.fields['my_field'] = my_field

现在，在shell（在所有导入之后...）

person = Person.objects.get(first_name='Jacob')
person.first_name # Prints 'Jacob', correct!
form = PersonForm(instance=person, last_name='Smith', my_field='test123')
form['first_name'].value() # -> 'Jacob', that's right
form['last_name'].value() # -> nothing, I expected 'Smith'
form['my_field'].value() # -> nothing, I would like to see 'test123'

我认为我在互联网上挖掘得很深，但找不到此类问题的解决方案。

Answer 1

您必须设置初始值。在你的初始化中尝试用下面的代码替换。

self.fields['last_name'].initial = last_name
self.fields['my_field'].initial = my_field

创建表单实例时也可以传递初始值。

form = PersonForm(instance=person, initial={'last_name'='Smith', 'my_field'='test123'})

这是推荐的方法。根本不必重写 init 方法。