In a Django form, how do I make a field readonly (or disabled) so that it cannot be edited?

Question

In a Django form, how do I make a field read-only (or disabled)?

When the form is being used to create a new entry, all fields should be enabled - but when the recor

Answer 1

I made a MixIn class which you may inherit to be able to add a read_only iterable field which will disable and secure fields on the non-first edit:

(Based on Daniel's and Muhuk's answers)

from django import forms
from django.db.models.manager import Manager

# I used this instead of lambda expression after scope problems
def _get_cleaner(form, field):
    def clean_field():
         value = getattr(form.instance, field, None)
         if issubclass(type(value), Manager):
             value = value.all()
         return value
    return clean_field

class ROFormMixin(forms.BaseForm):
    def __init__(self, *args, **kwargs):
        super(ROFormMixin, self).__init__(*args, **kwargs)
        if hasattr(self, "read_only"):
            if self.instance and self.instance.pk:
                for field in self.read_only:
                    self.fields[field].widget.attrs['readonly'] = "readonly"
                    setattr(self, "clean_" + field, _get_cleaner(self, field))

# Basic usage
class TestForm(AModelForm, ROFormMixin):
    read_only = ('sku', 'an_other_field')