Django在For循环中使用过滤器中的变量

Question

我试图使用父对象获得子对象/字段值。父变量是for loop中的一个变量，我似乎不能把它交给custom tag。

#custom_tags.py
@register.simple_tag()
def assigned_to(sample):
#sample=sample.pk
return Lab_Request.objects.filter(sample=sample).first().lab.lab_name
@register.filter()
def assigned_too(sample):
#sample=sample.pk
return Lab_Request.objects.filter(sample=sample).first().lab.lab_name

#sample.html
{% for sample in samples %}
{% static sample.0|assigned_too %}
{% if user.profile.employee.pk == sample.inspector.employee.pk or perms.ics.view_sample %}
<tr>
<td class="column1">{{ sample.sample_date }}</td>
<td class="column2">{{ sample.status|sample_status_options }}</td>
<td class="column3"><a href="#">{{ sample.sample_number }}</a></td>
<td class="column4"><a href="#">{{ sample.order.customer.customer_name }}</a></td>
<td class="column5"><a href="#">{{ sample.lab_request.placeholder_to_be_replaced }}{{ sample.lab_request.lab.lab_name }}{{ sample.inspection_request.inspector.employee.employee_first_name }}</a></td>
<td class="column6">{{ sample.date_modified|date:'M. d, Y'  }}</td>
</tr>
{% endif %}
{% endfor %}

{% static sample|assigned_too %}是我挣扎的部分。我也试着写一个函数，叫它像{% assigned_to {{ sample }} %}。如果我使用{% static 1|assigned_too %}，它确实有效，但它不会像需要的那样迭代我的循环。我不确定我是不是用了最复杂的方法。我只是想从父的孩子，如{{ sample.lab_request.lab.lab_name }}，其中sample是一个父对象和lab_request是一个子模型的信息。

编辑:

#views.py
class SampleHomeView(ListView):
model = Sample
samples = Sample.objects.all
context_object_name = 'samples'
template_name = 'ics/sample.html'
ordering = ['-sample_date']
paginate_by = 10

#urls.py
path('sample/', SampleHomeView.as_view(), name='sample-home'),

#models.py
class Lab_Request(models.Model):
#Add stuff here
placeholder_to_be_replaced = models.CharField(max_length=1)
lab = models.ForeignKey(Lab, on_delete=models.CASCADE, null=True, blank=True)
sample = models.ForeignKey(Sample, on_delete=models.CASCADE)
class Sample(models.Model):
order = models.ForeignKey(Order, on_delete=models.CASCADE)
employee = models.ForeignKey(Employee, on_delete=models.CASCADE)
status = models.CharField(max_length=2, choices=SAMPLE_STATUS_OPTIONS, default="01")
class Order(models.Model):
order_number = models.CharField(max_length=19, unique=True, editable=False, default=get_order_number)
status = models.CharField(max_length=2, choices=ORDER_STATUS_OPTIONS)
specification = models.ForeignKey(Specification, on_delete=models.CASCADE, null=True, blank=True) #Needs work to determine which spec is appropriate
customer = models.ForeignKey(Customer, on_delete=models.CASCADE)
user = models.ForeignKey(User, on_delete=models.CASCADE)
class Lab(models.Model):
status = models.CharField(max_length=2, choices=STATUS_OPTIONS)
lab_name = models.TextField(max_length=100, unique=True)

Answer 1

好吧，我明白了。我需要用稍微不同的方式把孩子叫给父母。我需要使用{{ sample.lab_request_set.all.0.lab }}而不是{{ sample.lab_request.lab }}

对于将来需要此功能的任何人，如果您不在ForeignKey中设置相关名称，那么它将是parent_model_name.child_model_name_set.all，这将为您提供一个查询集，然后您可以遍历或仅选择第一个，就像我在.all末尾使用.0一样。这在模板中工作。如果您需要在python文件中使用它，那么您将使用parent_model_name.child_model_name_set.all()

调用该函数。