相关疑难解决方法(0)

我有一个抽象的模型类UploadItem来处理上传的文件.我希望每个子类能够定义upload_to路径.为此,我将回调传递给FileField的构造函数.

这是一个例子:

class UploadItem(models.Model):
    file = models.FileField(upload_to=UploadItem.get_directory) 


    class Meta:
        abstract = True
# I want videos to be storred in 'videos/' directory
class Video(UploadItem):
    def get_directory(self, instance, filename):
        return 'videos/'

但这不起作用,我收到此错误:

file = models.FileField(upload_to=UploadItem.get_directory) 
NameError: name 'UploadItem' is not defined