使用实例进行表单验证

ImageField

# in model
class UserProfile(models.Model):
    user = models.ForeignKey(User, unique=True)
    avatar = models.ImageField(upload_to=\'images/%Y/%m/%d\', blank=True)

class ProfilePictureForm(ModelForm):
    class Meta:
        model = UserProfile
        fields = (\'avatar\', \'headline\')

    def clean_avatar(self):
        if not self.cleaned_data[\'avatar\']:
            raise forms.ValidationError(\'Oops, looks like you forgot to attach an image!\')
        else:
            return self.cleaned_data[\'avatar\']

# in views
def getting_started_pic(request):
    username = request.session.get(\'username\')
    profile = UserProfile.objects.get(user=username)
    if request.method == \'POST\':
        form = ProfilePictureForm(request.POST, request.FILES)
        if form.is_valid():
            form = ProfilePictureForm(request.POST, request.FILES, instance = profile)
            form.save()
            return render_to_response (...)

instance = profile