variables as parameters in field options
I want to create a model, that will set editable=False on creation, and editable=True on editing item. I thought it should be something like this:
home = models.ForeignKey(Team, editable=lambda self: True if self.id else False)
But it doesn't work. Maybe something with overriding the init can help me, but i don't sure what can do the trick. I know i can check for self.id in save() method, but is too late, i want this kind of logic in admin app when im filling the fields.
Asked by: Lana430 | Posted: 28-01-2022
Answer 1
Add the following (a small extension of this code) to your admin.py:
from django import forms
class ReadOnlyWidget(forms.Widget):
def __init__(self, original_value, display_value):
self.original_value = original_value
self.display_value = display_value
super(ReadOnlyWidget, self).__init__()
def render(self, name, value, attrs=None):
if self.display_value is not None:
return unicode(self.display_value)
return unicode(self.original_value)
def value_from_datadict(self, data, files, name):
return self.original_value
class ReadOnlyAdminFields(object):
def get_form(self, request, obj=None):
form = super(ReadOnlyAdminFields, self).get_form(request, obj)
fields = getattr(self, 'readonly', [])
if obj is not None:
fields += getattr(self, 'readonly_on_edit', [])
for field_name in fields:
if field_name in form.base_fields:
if hasattr(obj, 'get_%s_display' % field_name):
display_value = getattr(obj, 'get_%s_display' % field_name)()
else:
display_value = None
form.base_fields[field_name].widget = ReadOnlyWidget(getattr(obj, field_name, ''), display_value)
form.base_fields[field_name].required = False
return form
You can then specify that certain fields should by readonly when the object is edited:
class PersonAdmin(ReadOnlyAdminFields, admin.ModelAdmin):
readonly_on_edit = ('home',)
admin.site.register(Person, PersonAdmin)
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