Add class attributes to option tags of select menu on Django projects.

forms.py

# -*- coding: utf-8 -*-
from django import forms
from myapp.models import DataGroup # Overwrite this to your model
from django.utils.encoding import force_text
from django.utils.safestring import mark_safe
from django.utils.html import format_html

class DataGroupSelect(forms.widgets.Select):
    
    def render_option(self, selected_choices, option_value, option_label):
        option_value = force_text(option_value)
        if option_value in selected_choices:
            selected_html = mark_safe(' selected="selected"')
            if not self.allow_multiple_selected:
                # Only allow for a single selection.
                selected_choices.remove(option_value)
        else:
            selected_html = ''
        # get class attrs (customize class_attr by yourself)
        class_attr = 'xxxxxx'
        return format_html('<option value="{0}"{1} class="{3}">{2}</option>',
                           option_value,
                           selected_html,
                           force_text(option_label),
                           class_attr)

class DataGroupModelChoiceField(forms.ModelChoiceField):
    
    def __init__(self,*args,**kwargs):
        kwargs['widget'] = DataGroupSelect
        super(DataGroupModelChoiceField, self).__init__(*args,**kwargs)

class MyForm(forms.Form):
    datagroup_id = DataGroupModelChoiceField(queryset=DataGroup.objects.all())

This one save my days!!!!!!! Thanks a lot!