django - created custom year drop down field

Question

I've created year dropdown field. Here is a code. It is showing in admin section. But when i tried to save the field. I get validation error "Value u'2013' is not a valid choice" Can someone help me? thanks

# fields.py

import datetime

from django.db import models

YEAR_CHOICES = []
for r in range(1980, (datetime.datetime.now().year+1)):
    YEAR_CHOICES.append((r, r))


class YearDropdownField(models.CharField):
    def __init__(self, *args, **kwargs):
        kwargs.setdefault('editable', True)
        kwargs.setdefault('max_length', 4)
        kwargs.setdefault('choices', YEAR_CHOICES)
        kwargs.setdefault('default', datetime.datetime.now().year)
        super(YearDropdownField, self).__init__(*args, **kwargs)

# models.py

year = YearDropdownField(_('Year'))

Answer 1

尝试

    for r in range(1980, (datetime.datetime.now().year+1)):
        YEAR_CHOICES.append((r, unicode(r)))