Question

When the clean() method of my Django form detects an error, I’d like the form fields to redisplay as empty instead of filling in whatever input the user provided.

How do I do this? Is it a property of the form field itself, or is it done in the clean() method? I tried manipulating self.cleaned_data[‘fieldname’], but that did not work.

Thanks!

Answer 1

You need to set the data attribute of the field to ” in your clean method:

class MyForm(forms.Form):
    name = forms.CharField(max_length=50)

    def clean_name(self):
        name = self.cleaned_data['name']
        if name == 'Bob':
            raise forms.ValidationError(u'Name cannot be "Bob"')
            self.data['name'] = ''
        return name

Hope that helps you out.

[Edit]

Here’s an expanded example that is working for me in Django 1.3.

#models.py
from django.db import models

class ContactRequest(models.Model):
    name = models.CharField(max_length=100)
    email = models.EmailField()
    subject = models.CharField(max_length=255)
    message = models.TextField()
    response_returned = models.BooleanField(default=False)

    def __unicode__(self):
        return self.name


#forms.py
class ContactRequestForm(forms.ModelForm):
    class Meta:
        model = ContactRequest
        exclude = ('response_returned',)

    def clean_email(self):
        email = self.cleaned_data['email']
        if email != '[e-mail]':
            self.data['email'] = ''
            raise forms.ValidationError(u'Email is not [e-mail]')
        return email

[Edit]
Here’s an additional example that clears all fields if a condition isn’t met in a clean method. This works for me in Django 1.1.4.

#forms.py
from django import forms

class ContactForm(forms.Form):
    name = forms.CharField(max_length=50)
    email = forms.EmailField()

    def clean(self):
        cleaned_data = self.cleaned_data
        name = cleaned_data.get('name')
        email = cleaned_data.get('email')

        if email == '[e-mail]' and name == 'test':
            for k, _ in self.fields.iteritems():
                self.data[k] = ''
            raise forms.ValidationError(u'Email cannot be "[e-mail]" and name cannot be "test"')
        return cleaned_data