Django:在模型中添加一个字段

Question

我想在ModelForm中添加一个额外的字段.这似乎很容易,但我收到以下错误:

Django Version: 1.4 pre-alpha SVN-16573
Exception Type: TypeError
Exception Value:    
argument of type 'NoneType' is not iterable
Exception Location: /usr/local/lib/django-trunk/django/forms/models.py in construct_instance, line 39
Python Executable:  /usr/bin/python
Python Version: 2.6.6

这是代码:

class NodeForm(forms.ModelForm):
    password2 = forms.CharField(max_length=20, required=True, widget=forms.PasswordInput())

    class Meta:
        model = Node

    def __init__(self, *args, **kwargs):
        super(NodeForm, self).__init__(*args, **kwargs)
        # css classes for fields
        for v in self.fields:
            self.fields[v].widget.attrs['class'] = 'text ui-widget-content ui-corner-all'

    def clean(self):
        ''' Calls parent clean() and performs additional validation for the password field '''
        super(NodeForm, self).clean()
        password = self.cleaned_data.get('password')
        password2 = self.cleaned_data.get('password2')
        # password and password2 must be the same
        if password != password2:
            raise forms.ValidationError('I due campi password non corrispondono.')

我无法修复它.我究竟做错了什么？

Answer 1

应该返回从清理数据clean的方法记录在这里 就是说:

def clean(self):
    # perform checks
    return self.cleaned_data