Django MultiSelectField Error: 'super' object has no attribute '_get_flatchoices'

Question

I tried to use Django Multiselectfield library but i got this error:

I already installed it properly by command: pip install django-multiselectfield

I also added in my settings.py

INSTALLED_APPS = [
    .....
    'multiselectfield',
]

My models.py:

from multiselectfield import MultiSelectField
from django.db import models
CATEGORY = [
    ('CP', 'Computer Programming'),
    ('LG', 'Language'),
    ('MA', 'Mathematics'),
    ('BM', 'Business Management'),
    ('GK', 'General Knowledge')
]

class Quiz(models.Model):
    ...
    title = models.CharField(max_length=256)
    category = MultiSelectField(choices=CATEGORY, max_choices=2, max_length=5)
    ...
        
    def save(self, *args, **kwargs):
        if not self.category:
            self.category = ['GK']
        super(Quiz, self).save(*args, **kwargs)
        
    def __str__(self):
        return self.title

The error: 'super' object has no attribute '_get_flatchoices'

However this is located in the Multiselectfield library code. Because of this error, even my data cannot be saved. I tried to find out what am I missing, but I have no idea.

Any idea what's wrong with my code? Appreciate your help ^_^

Answer 1

The current version of Multiselectfield is incompatible with Django 5.0. There is no _get_flatchoices in django's CharField anymore, instead Django provides flatchoices directly. Therefore, the following code in ../multiselectfield/db/fields.py should be removed.

def _get_flatchoices(self):
    flat_choices = super(MultiSelectField, self)._get_flatchoices()

    class MSFFlatchoices(list):
        # Used to trick django.contrib.admin.utils.display_for_field into
        # not treating the list of values as a dictionary key (which errors
        # out)
        def __bool__(self):
            return False
        __nonzero__ = __bool__
    return MSFFlatchoices(flat_choices)
flatchoices = property(_get_flatchoices)

Thanks for aliceni81

For further information, you can check on https://github.com/goinnn/django-multiselectfield/issues/141

Answer 2

I could not find the db/fields.py file. I found out that it is located in your python folder. Mine was located at: C:\Users...\AppData\Local\Programs\Python\Python312\Lib\site-packages\multiselectfield\db\fields.py Then I right-clicked the file and opened fields.py using VS Code. Simply comment out ( Ctrl + / ) the section below, found on lines 78-89 of the python file.

# def _get_flatchoices(self):
#     flat_choices = super(MultiSelectField, self)._get_flatchoices()

#     class MSFFlatchoices(list):
#         # Used to trick django.contrib.admin.utils.display_for_field into
#         # not treating the list of values as a dictionary key (which errors
#         # out)
#         def __bool__(self):
#             return False
#         __nonzero__ = __bool__
#     return MSFFlatchoices(flat_choices)
# flatchoices = property(_get_flatchoices)

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