Django form field choices, adding an attribute

Here is a general solution to allow attributes in options in a Select widget, SelectMultiple widget and also in Select2 widgets.

It has been tested on Django 2.1 and should work for other versions as well (tell me in comments).

from django.forms.widgets import Select, SelectMultiple

class SelectWOA(Select):
    """
    Select With Option Attributes:
        subclass of Django's Select widget that allows attributes in options, 
        like disabled="disabled", title="help text", class="some classes",
              style="background: color;"...

    Pass a dict instead of a string for its label:
        choices = [ ('value_1', 'label_1'),
                    ...
                    ('value_k', {'label': 'label_k', 'foo': 'bar', ...}),
                    ... ]
    The option k will be rendered as:
        <option value="value_k" foo="bar" ...>label_k</option>
    """

    def create_option(self, name, value, label, selected, index, 
                      subindex=None, attrs=None):
        if isinstance(label, dict):
            opt_attrs = label.copy()
            label = opt_attrs.pop('label')
        else: 
            opt_attrs = {}
        option_dict = super(SelectWOA, self).create_option(name, value, 
            label, selected, index, subindex=subindex, attrs=attrs)
        for key,val in opt_attrs.items():
            option_dict['attrs'][key] = val
        return option_dict

Here is an example that you can try in your forms.py:

choices = [('b', 'blue'),
           ('g', {'label': 'green', 'disabled': 'disabled'}),
           ('c', {'label': 'cyan', 
                  'title': 'Kind of violet',
                  'style': 'background: cyan;',
                 }),
           ('r', 'red'), ]

colors = forms.ChoiceField(
    label="Colors",
    choices=choices,
    widget=SelectWOA)

The colors field can be rendered in Django shell to check the result:

(myvenv) $ ./manage.py shell
>>> from myapp.forms import *
>>> choices = ...
>>> colors = ...
>>> colors.widget.render('mycolors','')
'''<select name="mycolors">
      <option value="b">blue</option>
      <option value="g" disabled="disabled">green</option>
      <option value="c" title="Kind of violet" style="background: cyan;">cyan</option>
      <option value="r">red</option>
 </select>'''

To allow multiple selections, add this:

class SelectMultipleWOA(SelectWOA, SelectMultiple):
    """ 
    SelectMultipleWOA widget works like SelectMultiple, with options attrs.
    See SelectWOA.
    """
    pass

colors = forms.MultipleChoiceField(
    label="Colors",
    choices=choices,
    widget=SelectMultipleWOA)

It will render <select name="mycolors" multiple>...<\select>.

You can use SelectWOA and SelectMultipleWOA to extend the Select2 widgets:

from django_select2.forms import Select2Mixin

class Select2MultipleWidgetWOA(Select2Mixin, SelectMultipleWOA):
    """
    Select2 drop in widget for multiple select.
    Works just like Select2MultipleWidget but with options attrs.
    """
    pass

colors = forms.MultipleChoiceField(
    label="Colors",
    choices=choices,
    widget=Select2MultipleWidgetWOA(
        attrs={'data-placeholder': 'Any color',
               'data-close-on-select': 'false',
               'style': 'width:280px; height:36px;',
               'title': 'Type a word to filter the menu',}
    )
)

It will render something like:

'''<select name="mycolors" data-placeholder="Any color" 
    class="django-select2" data-minimum-input-length="0" multiple 
    style="width:280px; height:36px;" data-close-on-select="false" 
    data-allow-clear="false" title="Type a word to filter the menu">
       <option value="b">blue</option>
       <option value="g" disabled="disabled">green</option>
       <option value="c" title="Kind of violet" style="background: cyan;">cyan</option>
       <option value="r">red</option>
    </select>'''

You'd have to subclass the field to take whatever means of specifying the title you'd like and the widget to display the new attribute.

If you had something like this (note: entirely untested):

from django import forms
from django.utils.html import escape
from django.utils.encoding import force_unicode

class SelectWithTitles(forms.Select):
    def __init__(self, *args, **kwargs):
        super(SelectWithTitles, self).__init__(*args, **kwargs)
        # Ensure the titles dict exists
        self.titles = {}

    def render_option(self, selected_choices, option_value, option_label):
        title_html = (option_label in self.titles) and \
            u' title="%s" ' % escape(force_unicode(self.titles[option_label])) or ''
        option_value = force_unicode(option_value)
        selected_html = (option_value in selected_choices) and u' selected="selected"' or ''
        return u'<option value="%s"%s%s>%s</option>' % (
            escape(option_value), title_html, selected_html,
            conditional_escape(force_unicode(option_label)))

class ChoiceFieldWithTitles(forms.ChoiceField):
    widget = SelectWithTitles

    def __init__(self, choices=(), *args, **kwargs):
        choice_pairs = [(c[0], c[1]) for c in choices]
        super(ChoiceFieldWithTitles, self).__init__(choices=choice_pairs, *args, **kwargs)
        self.widget.titles = dict([(c[1], c[2]) for c in choices])

...you should be able to do this:

PLANNING_CHOICES_WITH_TITLES = (
    ('0', 'Every morning', 'bla1'),
    ('1', 'Every night',   'bla2'),
    ('2', 'Never',         'bla3'),
)

planning = forms.ChoiceFieldWithTitles(
    required=True, choices=PLANNING_CHOICES_WITH_TITLES)