python - 我无法从 Django 中的模板访问相关字段，但它可以在 shell 中工作，我做错了什么？

Question

编辑:在底部添加模型类。

我有这个 View 代码，它从 Django 表单获取输入并使用它在数据库中搜索值。

class SearchResults(generic.FormView):
    template_name = 'search_results.html'
    context_object_name = 'submissions'
    form_class = SearchForm
    model = Submissions

    def get_context_data(self, **kwargs):
        context = super(SearchResults, self).get_context_data(**kwargs)
        level = self.request.GET['level']
        media_type = self.request.GET['media_type']
        tags = MajorTags.objects.filter(
            tag__icontains=self.request.GET['search'])
        tag_ids = [t.id for t in tags]
        context['results'] = Submissions.objects.filter(
            tags__id__in=tag_ids,
            level__contains=level,
            media_type__contains=media_type)
        return context

然后最终由该模板呈现。

{% extends "base.html" %}

{% block content %}
<form action="{% url 'search_results' %}" method="get" class="global-search">
    {% csrf_token %}
    {{ form }}.
    <input type="submit" value="Go" />
</form>
<ul>
    {% for resource in results %}
    <li> <a href="/resources{%url 'resource' resource.id%}"> {{resource.url}} </a> {{resource.stats_set}}
        </li>
    {% endfor %}

</ul>
{% endblock %}

问题是 {{resource.stats_set}} 在模板中没有返回任何内容。 (确切的输出是 doc_sub.Stats.None。)但是，当我在 shell 中运行以下代码时，我得到了我正在寻找的结果。

from doc_sub.models import MajorTags, Submissions
tags = MajorTags.objects.filter(tag__icontains='Theology')
tag_ids = [t.id for t in tags]
level = 'Introductory'
media_type='HTML'
context = Submissions.objects.filter(tags__id__in=tag_ids, level__contains=level,  media_type__contains=media_type)
for i in context:
    print i.stats_set.values()

以下是必要的模型:

class Submissions(models.Model):
    LEVEL = (
        ('Introductory', 'Introductory'),
        ('Intermediate', 'Intermediate'),
        ('Academic', 'Academic'),
    )

    MEDIA_TYPE = (
        ('HTML', 'HTML'),
        ('PDF', 'PDF'),
        ('Video', 'Video'),
        ('Other', 'Other'),
    )
    id = models.AutoField(primary_key=True)
    url = models.URLField(unique=True)
    tags = models.ForeignKey(MajorTags, default=0)
    level = models.CharField(choices=LEVEL, max_length=25)
    media_type = models.CharField(choices=MEDIA_TYPE, max_length=25)

    def __unicode__(self):
        return self.url
class Stats(models.Model):
    url = models.ForeignKey(Submissions)
    id = models.AutoField(primary_key=True)
    avg = models.FloatField(default=0)
    std_dev = models.FloatField(default=0)

    def __unicode__(self):
        return self.url.url + " " + str(self.avg)

Answer 1

嗯，我明白了。如果我很聪明并且使用 RTFM，我可能会更快地弄清楚这一点，但是，我试图以错误的方式访问该值。我正在这样做: print t.stats_set.values()[0]['avg'] 就像我在正常的 python 上下文中访问值一样，但我需要这样做: 资源.stats_set.values.0.avg