django实现模型字段动态choice的操作

class PushRuleForm(forms.ModelForm):  
  def __init__(self, *args, **kwargs):
    if self.request.user.username in Const.TEST_USER_LIST:
      # 如果进入都是add添加新项的页面
      if not kwargs.get('instance'):
        # self.fields['test_mode'].initial = 1
        self.fields['test_mode'].choices = [(1,'Test')]
      # else:
      #   self.fields['test_mode'].choices = [choice for choice in [(0,'OnLine'),(1,'Test')] if self.instance.test_mode in choice]

class PushRuleAdmin:
  form = PushRuleForm
  def changeform_view(self, request, object_id=None, form_url='', extra_context=None):
    self.form.request = request
    return super(PushRuleAdmin, self).changeform_view(request, object_id, extra_context=extra_context)

class PushRule(models.Model):  
  test_mode  = models.IntegerField(verbose_name='TestMode', default=0, choices=[(0,'OnLine'),(1,'Test')])

class PushRuleAdmin:
  def render_change_form(self, request, context, add=False, change=False, form_url='', obj=None):
    context['test_user_list']=Const.TEST_USER_LIST
    return super(PushRuleAdmin, self).render_change_form(request, context, add=False, change=False, form_url='', obj=None)

  if (test_user_list.includes(username))
  {
    $("#id_test_mode > option[value='0']").remove();
  }

# models.py
class BookTagNum(object):
  OTHER = 1
  SCIENCE = 2
  SOCIAL_SCIENCES = 3
  ECONOMIC = 4
  COMPUTER = 5

class BOOK(models.Model):
  TAG_NUM_CHOICE = (
    (BookTagNum.OTHER, '其它'),
    (BookTagNum.SCIENCE, '科学类'),
    (BookTagNum.SOCIAL_SCIENCES, '社科类'),
    (BookTagNum.ECONOMIC, '经济类'),
    (BookTagNum.COMPUTER, '计算机类'),
  )
  tag = models.IntegerField(choices=TAG_NUM_CHOICE)

# view.py
def get(self, request):
 book = Book.obejects.filter(tag = BookTagNum.COMPUTER)