from django.db import models from django import forms from django.utils.text import capfirst class MultiSelectFormField(forms.MultipleChoiceField): widget = forms.CheckboxSelectMultiple def __init__(self, *args, **kwargs): self.max_choices = kwargs.pop('max_choices', 0) super(MultiSelectFormField, self).__init__(*args, **kwargs) def clean(self, value): if not value and self.required: raise forms.ValidationError(self.error_messages['required']) if value and self.max_choices and len(value) > self.max_choices: raise forms.ValidationError('You must select a maximum of %s choice%s.' % (apnumber(self.max_choices), pluralize(self.max_choices))) return value class MultiSelectField(models.Field): __metaclass__ = models.SubfieldBase def get_internal_type(self): return "CharField" def get_choices_default(self): return self.get_choices(include_blank=False) def _get_FIELD_display(self, field): value = getattr(self, field.attname) choicedict = dict(field.choices) def formfield(self, **kwargs): # don't call super, as that overrides default widget if it has choices defaults = {'required': not self.blank, 'label': capfirst(self.verbose_name), 'help_text': self.help_text, 'choices':self.choices} if self.has_default(): defaults['initial'] = self.get_default() defaults.update(kwargs) return MultiSelectFormField(**defaults) def get_db_prep_value(self, value): if isinstance(value, basestring): return value elif isinstance(value, list): return ",".join(value) def to_python(self, value): if isinstance(value, list): return value return value.split(",") def contribute_to_class(self, cls, name): super(MultiSelectField, self).contribute_to_class(cls, name) if self.choices: func = lambda self, fieldname = name, choicedict = dict(self.choices):",".join([choicedict.get(value,value) for value in getattr(self,fieldname)]) setattr(cls, 'get_%s_display' % self.name, func)