- Author:
- alecdotico
- Posted:
- July 16, 2013
- Language:
- Python
- Version:
- 1.5
- Score:
- 0 (after 0 ratings)
Sometimes we may need to generate a ModelChoiceField in which choices are generated at runtime, depending on the locale language. The snippet generates a ChoiceField based on a queryset and a specific attribute of the Model, ordering the choices by the attribute content in the locale language.
Usage example (inside a form declaration)
country = LazyModelChoiceField(sort_by='name', queryset = \
Country.objects.all, empty_label=_('All countries'), label=_('Country'))
Based on lsbardel LazyChoiceField implementation (snippet 1767)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | class LazyModelChoiceField(forms.ChoiceField):
'''
A Lazy ModelChoiceField, similar to LazyChoiceField
not overriding ModelChoiceField, since we need to convert the queryset into a tuple to sort it
This allows for dynamic choices generation every time an instance of a Form is created.
'''
def __init__(self, *args, **kwargs):
self.sort_by = kwargs.pop('sort_by', ())
self.queryset = kwargs.pop('queryset', ())
self.empty_label = kwargs.pop('empty_label', ())
super(LazyModelChoiceField, self).__init__(*args, **kwargs)
def __deepcopy__(self, memo):
result = super(LazyModelChoiceField, self).__deepcopy__(memo)
# requires of ugettext_lazy as _
result.choices = ()
for entry in self.queryset():
result.choices.append((entry.id, _(entry.__getattribute__(self.sort_by))))
result.choices.sort(lambda x, y: cmp(x[1], y[1]))
result.choices.insert(0, (0, self.empty_label))
return result
|
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