Django MultiValueField

Question

I'm struggling with some Django, where I want to make a custom MultiValueField combined with MultiWidget. I've read misc. tutorials, but it seem I'm missing something - most of them were quite old, which I suspect could be the reason.

I'm using Django 1.10.

Goal: Make a custom field that provides three dropdowns for a form. So far, no requirements to the contents of the dropdowns - first I just want to see them in my form :-)

I have a fields.py file, containing:

from django import forms
from widgets import MyCustomWidget

class MyCustomField(forms.MultiValueField):
  widget = MyCustomWidget

  def __init__(self, *args, **kwargs):
    fields = (
      forms.CharField(max_length=31),
      forms.CharField(max_length=31),
      forms.CharField(max_length=31),
    )
    super(MyCustomField, self).__init__(fields, *args, **kwargs)

  def compress(self, data_list):
    return "-".join(data_list)

And then there's a widgets.py, containing:

import re
from django import forms

class MyCustomWidget(forms.MultiWidget):
  def __init__(self, attrs=None):
    widgets = (
      forms.widgets.Select(attrs=attrs, choices=[("1", "1")]),
      forms.widgets.Select(attrs=attrs, choices=[("2", "2")]),
      forms.widgets.Select(attrs=attrs, choices=[("3", "3")]),
    )
    super(MyCustomWidget, self).__init__(widgets, attrs)


  def decompress(self, value):
    if value:
      return re.split(r"\-", value)
    return [None, None, None]

forms.py:

from django.forms import ModelForm
from django import forms

class MyCustomForm(forms.ModelForm):
  class Meta:
    model = MyCustomModel
    fields = ("name")

  name = forms.CharField(widget=MyCustomField)

This works fine when migrating, but I try to view the form, I get this error:

'MyCustomField' object has no attribute 'is_hidden'

I have tried to implement this attribute in MyCustomField, but then I get another error:

'MyCustomField' object has no attribute 'attrs'

These attributes should be provided by forms.MultiValueField, as far as I understand - thus I shouldn't need to write them myself.

In the template, I'm just using "{{ form }}" as I wan't to use Django's default layout.

I'm going nuts here and hope someone is able to help to the right path :-)

Kind regards, Kasper

Answer 1

I believe your mistake is on the line where you set the name name = forms.CharField(widget=MyCustomField). I haven't tested the codes thou.

from django.forms import ModelForm
from django import forms

class MyCustomForm(forms.ModelForm):
    class Meta:
        model = MyCustomModel
        fields = ("name")

    name = MyCustomField # This I believe is will fix your error