I'm trying to create a custom field for a ModelForm. I'm extending from ModelMultipleChoiceField and then overriding render and render_options, however, I keep getting this exception when just trying to import my form:
AttributeError: 'ModelMultipleChoiceField' object has no attribute 'to_field_name'
I'm not sure what I'm missing. I've tried even adding a to_field_name attribute to my new class, but that doesn't help. Here is my code:
class MultiSelect(ModelMultipleChoiceField):
def __init__(self, queryset, cache_choices=False, required=True,
widget=None, label=None, initial=None, help_text=None, *args, **kwargs):
super(MultiSelect, self).__init__(queryset, cache_choices, required, widget,
label, initial, help_text, *args, **kwargs)
def render_options(self, name, choices, selected_choices):
output = []
i = 0
for option_value, option_label in chain(self.choices, choices):
checked_html = (option_value in selected_choices) and u' checked="checked"' or ''
class_html = (i % 2 == 0) and u'even' or u'odd'
output.append('<li class="{0}"><input type="checkbox" name="{1}" value="{2}"{3}/>{4}</li>'
.format(class_html, name, escape(option_value), checked_html, escape(option_label)))
i += 1
def render(self, name, value, attrs=None, choices=()):
if value is None: value = []
final_attrs = self.build_attrs(attrs, name=name)
output = [u'<ul class="multiSelect">']
options = self.render_options(name, choices, value)
if options:
output.append(options)
output.append('</ul>')
return mark_safe(u'\n'.join(output))
class RoleForm(ModelForm):
class Meta:
model = Role
exclude = ('user_id',)
widgets = {
'permissions': MultiSelect(queryset=Permission.objects.all())
}
Whenever I simply do an from myapp.forms import RoleForm
, I get the error above.
Should I be adding something to my class that I'm missing?
You seem to have got confused between fields and widgets. You inherit from ModelMultipleChoiceField
, which (as the name implies) is a field, not a widget. But render
and render_options
are methods on widgets, not fields. And you've used your class in the widgets
dictionary.
I suspect you do mean to create a widget. You should inherit from a widget class, probably forms.CheckboxSelectMultiple
.