Source code for dash.fields

from django.db import models

__author__ = 'Artur Barseghyan <artur.barseghyan@gmail.com>'
__copyright__ = '2013-2021 Artur Barseghyan'
__license__ = 'GPL-2.0-only OR LGPL-2.1-or-later'
__all__ = (
    'OrderField',
)


[docs]class OrderField(models.IntegerField): """OrderField. @author http://djangosnippets.org/users/zenx/ @source http://djangosnippets.org/snippets/1861/ OrderField for models from //ianonpython.blogspot.com/2008/08/orderfield-for-django-models.html and updated to use a django aggregation function. This field sets a default value as an auto-increment of the maximum value of the field +1. Ignores the incoming value and instead gets the maximum plus one of the field. This works really well in combination with "sortable_list.js". There are several things you should know: * order field shall be null=True, blank=True * order field shall not be unique If above mentioned is True, you can use jQuery drag-n-drop widget in your Django-admin. See the following example: >>> class Media: # This belongs to your Admin class (admin.ModelAdmin) >>> js = [ >>> '/media/js/jquery-1.6.2.min.js', >>> '/media/js/jquery-ui-1.8.16.custom.min.js', >>> '/media/js/sortable_list.js' >>> ] """
[docs] def pre_save(self, model_instance, add): # if the model is new and not an update if model_instance.pk is None: records = model_instance.__class__.objects.aggregate( models.Max(self.name) ) if records: # get the maximum attribute from the first record and add # 1 to it try: value = records['{0}__max'.format(self.name)] + 1 except TypeError: value = 1 else: value = 1 # otherwise the model is updating, pass the attribute value through else: value = getattr(model_instance, self.attname) return value
# prevent the field from being displayed in the admin interface
[docs] def formfield_(self, **kwargs): return None