scj/apps/foundation/managers.py

#coding=utf-8

from django.db import models

from apps.exceptions import CustomError

class OptionManager(models.Manager):
    def _get_instance_by_type_and_id(self, type, id):
        instance = self.model.objects.filter(type=type, id=id).first()
        if not instance:
            raise CustomError(
                u'请从下拉列表中选择{0}。<br>如果{0}不在下拉列表中，请到“系统设置”-->“自定义项”添加。'.format(
                    self.model.TYPE_CHOICES[type][1]
                )
            )
        return instance