DateTimeField 对象没有属性 strftime

Question

我的主要代码是这样的：

  class Post(models.Model):

    title = models.CharField(max_length=200, unique=True)

    slug = models.SlugField(max_length=200, unique=True)

    author = models.ForeignKey(User, on_delete=models.CASCADE, related_name='blog_posts')

    updated_on = models.DateTimeField(auto_now=True)

    image = models.ImageField(upload_to='images/%Y/%m/%d/', blank=True)

    content = models.TextField()

    created_on = models.DateTimeField(auto_now_add=True)

    status = models.IntegerField(choices=STATUS, default=0)

    publishdate = created_on.strftime('%Y/%m')

    class Meta:

        ordering = ['-created_on']

    def __str__(self):

        return self.title

当我运行这段代码时，我得到：

'DateTimeField' object has no attribute 'strftime'

参考发布日期

strftime 与 datetime.datetime 一起使用，而 DateTimeField 转换为 datetime.datetime，那么我做错了什么？

我尝试转换为 datetime.datetime 无济于事

编辑：看到答案后，我想我应该验证我想要做什么

我正在尝试将日期添加到 urls.py 中的此网址：

   urlpatterns = [

      path('', views.PostList.as_view(), name='home'),

      path('<publishdate>/<slug:slug>', views.PostDetail.as_view(), name='post_detail'

]

编辑2：我已将代码更新为：

class Post(models.Model):

    title = models.CharField(max_length=200, unique=True)

    slug = models.SlugField(max_length=200, unique=True)

    author = models.ForeignKey(User, on_delete=models.CASCADE, related_name='blog_posts')

    updated_on = models.DateTimeField(auto_now=True)

    image = models.ImageField(upload_to='images/%Y/%m/%d/', blank=True)

    content = models.TextField()

    created_on = models.DateTimeField(auto_now_add=True)

    status = models.IntegerField(choices=STATUS, default=0)

    created_on_string = created_on.value_to_string(created_on)

    publishdate = strptime(created_on_string, '%Y/%m')

    class Meta:

        ordering = ['-created_on']

    def __str__(self):

        return self.title

Answer 1

在类级别，created_on是 a DateTimeField，而不是datetime对象（不是类）所拥有的Post 对象。如果你想添加一个格式化它的属性，你可以使用：class Post(models.Model):&nbsp; &nbsp; # …&nbsp; &nbsp; created_on = models.DateTimeField(auto_now_add=True)&nbsp; &nbsp; @property&nbsp; &nbsp; def publishdate(self):&nbsp; &nbsp; &nbsp; &nbsp; return self.created_on.strftime('%Y/%m')&nbsp; &nbsp; # …话虽如此，格式化数据通常不是模型的任务。模型用于存储和表示数据。例如，在模板中，您可以使用|date模板标签 [Django-doc]以datetime指定格式格式化对象。对于给定的Post对象post，您可以将其格式化为：{{ post.created_on|date:'Y/m' }}对于 URL，您可以使用两个参数：urlpatterns = [&nbsp; &nbsp; path('', views.PostList.as_view(), name='home'),&nbsp; &nbsp; path(&nbsp; &nbsp; &nbsp; &nbsp; '<int:year>/<int:month>/<slug:slug>',&nbsp; &nbsp; &nbsp; &nbsp; views.PostDetail.as_view(),&nbsp; &nbsp; &nbsp; &nbsp; name='post_detail'&nbsp; &nbsp; )]在您看来，您可以使用以下内容进行过滤：class PostDetail(DetailView):&nbsp; &nbsp; model = Post&nbsp; &nbsp; def get_queryset(self, *args, **kwargs):&nbsp; &nbsp; &nbsp; &nbsp; return super().get_queryset(*args, **kwargs).filter(&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; created_on__year=self.kwargs['year'],&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; created_on__month=self.kwargs['month']&nbsp; &nbsp; &nbsp; &nbsp; )在模板中，您可以使用以下对象链接到视图post：{% url 'post_detail' post.created_on.year post.created_on.month post.slug %}

Answer 2

难道不应该通过self在类级别向属性添加 a 来工作吗？publishdate&nbsp;=&nbsp;self.created_on.strftime('%Y/%m')