Question

当用户创建模型House的实例时，我正在尝试创建Car实例。

Models.py

class House(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, default=None)
    address = models.CharField(max_length=100)

    def __str__(self):
        return self.user.username

class Car(models.Model):
    user = models.ForeignKey(User, on_delete=models.CASCADE, default=None)
    makemodel = models.CharField(max_length=100)

    def __str__(self):
        return self.user.username


def create_car(sender, **kwargs):
    if kwargs['created']:
        car = Car.objects.create(user=kwargs['instance'])

post_save.connect(create_car, sender=House)   #have to figure out how to have multiple senders

当我进入管理员并为任何用户创建House模型的实例时，我收到以下错误。

"Cannot assign "<House: jason>": "Car.user" must be a "User" instance."

任何想法都将不胜感激！

Answer 1

您需要传递user参数用户实例，但在create_car，因为发件人是House，实例参数的类型为House。

您可以这样做：

def create_car(sender, **kwargs):
    if kwargs['created']:
        car = Car.objects.create(user=kwargs['instance'].user)

在保存后创建模型实例

1 个答案: