Access ForeignKey set directly in template in Django

问题

I have this simplified model:

class Item(models.Model):
    name = models.CharField(max_length=120)

class ItemImage(models.Model):
    image = models.ImageField(upload_to='upload_dir')
    item = models.ForeignKey(Item)

An Item can have many ItemImages. I also have a template rendering the following data set from the view:

items = Item.objects.all()

So now I would want to do something like this in the template:

{% for item in items %}
<div>
    {{ item.name }}<br>
    <img src="{{ item.itemimage_set.all()[0] }}">
</div>
{% endfor %}

But obviously that's not possible. Not from the template directly, at least.

What is the proper way to get the equivalent of the first image inside the template?

回答1:

{% with item.itemimage_set.all|first as image %}
  <img src="{{ image.url }}" />
{% endwith %}

回答2:

Or you could add a method to your Item model:

def get_first_image(self):
    return self.itemimage_set.all()[0]

and then call this method in your template:

{{ item.get_first_image }}

Or you could use:

{{ item.itemimage_set.all.0 }}

and to get the first image's url:

<img src="{{ item.itemimage_set.all.0.url }}">

Though if you need more flexibility (more than one picture in certain cases, etc.) it's probably best to write a little templatetag.

回答3:

One possible way would be to iterate over all the ItemImages like so:

{% for item in items %}
<div>
    {{ item.name }}<br>
    {% for image in item.itemimage_set.all %}
    <img src="{{ image.image.url }}">
    {% endfor %}
</div>
{% endfor %}

回答4:

If you want the first picture from set you can do:

{% for item in item.image_set.all %}

{{if forloop.first }}
<img src="{{ item.url }}">
{% endif %}

{% endfor %}

But i also love Andray solution with 'with'

回答5:

this worked for me, use the related_name in your models.

models.py

class Building(models.Model):
    address  = models.CharField(max_length=200, blank=True, null=True)
    city     = models.CharField(max_length=200, blank=True, null=True)

class Space(models.Model):
    title     = models.CharField(max_length=200, blank=True, null=True)
    building  = models.ForeignKey(Building, related_name="spaces_of_this_building")

buildings.html

{% for space in building.spaces_of_this_building.all %}
  {{ space.size }}
{% endfor %}

来源：https://stackoverflow.com/questions/6217638/access-foreignkey-set-directly-in-template-in-django

标签

django

django-models