Django模板中的嵌套循环 [英] Nested loop in Django template

问题描述

我无法理解这一点。我需要以某种方式访问​​父循环中的对象，但我不知道如何。这是我到目前为止所做的。我使用 XXX 标记了代码中存在问题的部分：
$ b

模板：

  {％for item in ingrcat％} 
< h2> {{item.name}}< / h2> 
< ul> 
 {％for ingr in XXX％} 
< li>< a href =＃id =i {{ingr.id}}> {{ingr.name}}< ; / A>< /锂> 
 {％endfor％} 
< / ul> 
 {％endfor％} 
  

XXX - 应该是

查看：

  def home（request）：$ b $如果request.user.is_authenticated（）：
 username = request.user.username 
 email = request.user.email 
 foods = Food.objects.filter（user = request.user）.order_by（'name'）
 ingredients = Ingredience.objects.filter（user = request.user ）.order_by（'name'）
 ingrcat = IngredienceCategory.objects.filter（user = request.user）
 
 context = {} 
 for i in ingredients：
 context [i.category.name.lower（）] = context.get（i.category.name.lower（），[]）+ [i] 
 
 newcontext = {'foods'：食物，配料：配料，'ingrcat'：ingrcat，'用户名'：用户名，'email'：电子邮件，} 
 else：
 context = {} 
 newcontext = {} 
 $ b $ context = dict（context.items（）+ newcontext.items（））
 
 return render_to_response（'home.html'，context，context_instance = RequestContext（request））
  

Models：

  from django.db import models $ b $ from django.contrib.auth.models import User 
 
类IngredienceCategory（models.Model）：
 name = models.CharField（max_length = 30）
 user = models.ForeignKey（User，null = True，blank = True ）
 $ b $ class Meta：
 verbose_name_plural =元素类别
 
 def __unicode __（self）：
返回self.name 
 
 
类成分（models.Model）：
 name = models.CharField（max_length = 30）
 category = models.ForeignKey（IngredienceCategory，null = True，blank = True）
 user = models.ForeignKey（User，null = True，blank = True）
 
 class Meta：
 verbose_name_plural =Ingredients
 $ b $ def __unicode __（self）：
 return self.name 
 
 
 class Food（models.Model）：
 name = models.CharField（max_length = 30）
 ingredients = models.ManyToManyField（Ingredience）
 html_id = models.CharField（max_length = 30，null = True，blank = True）
 user = models.ForeignKey（User，null = True，blank = True）
 $ b $ class Meta：
 verbose_name_plural =Foods
 $ b $ def __unicode __（self）：
 return self.name 
  

解决方案

关系。

pre $ lt; code> {％for item in ingrcat％}
< h2> {{item.name}}< ; / H2>
< ul>
{item for item.ingredience_set.all％中的%%}
< li>< a href =＃id =i {{ingr.id}}> {{ingr。 name}}< / a>< / li>
{％endfor％}
< / ul>
{％endfor％}

查看文档：

https：// docs。 djangoproject.com/en/dev/topics/db/queries/#following-relationships-backward

I can't get my head around this. I need to somehow access the object in the parent loop but I'm not sure how. Here is what I've come up with so far. I marked the problematic area in the code with XXX:

Template:

{% for item in ingrcat %}
    <h2>{{ item.name }}</h2>
    <ul>
        {% for ingr in XXX %}
        <li><a href="#" id="i{{ ingr.id }}">{{ ingr.name }}</a></li>
        {% endfor %}
    </ul>
{% endfor %}

XXX - should be a list of ingredients belonging to the ingredience category which is currently being looped through in the parent loop.

View:

def home(request):
    if request.user.is_authenticated():
        username = request.user.username
        email = request.user.email
        foods = Food.objects.filter(user=request.user).order_by('name')
        ingredients = Ingredience.objects.filter(user=request.user).order_by('name')
        ingrcat = IngredienceCategory.objects.filter(user=request.user)

        context = {}
        for i in ingredients:
            context[i.category.name.lower()] = context.get(i.category.name.lower(), []) + [i]

        newcontext = {'foods': foods, 'ingredients': ingredients, 'ingrcat': ingrcat, 'username': username, 'email': email,}
    else:
        context = {}
        newcontext = {}

    context = dict(context.items() + newcontext.items())

    return render_to_response('home.html', context, context_instance=RequestContext(request))

Models:

from django.db import models
from django.contrib.auth.models import User

class IngredienceCategory(models.Model):
    name = models.CharField(max_length=30)
    user = models.ForeignKey(User, null=True, blank=True)

    class Meta:
        verbose_name_plural = "Ingredience Categories"

    def __unicode__(self):
        return self.name


class Ingredience(models.Model):
    name = models.CharField(max_length=30)
    category = models.ForeignKey(IngredienceCategory, null=True, blank=True)
    user = models.ForeignKey(User, null=True, blank=True)

    class Meta:
         verbose_name_plural = "Ingredients"

    def __unicode__(self):
        return self.name


class Food(models.Model):
    name = models.CharField(max_length=30)
    ingredients = models.ManyToManyField(Ingredience)
    html_id = models.CharField(max_length=30, null=True, blank=True)
    user = models.ForeignKey(User, null=True, blank=True)

    class Meta:
        verbose_name_plural = "Foods"

    def __unicode__(self):
        return self.name

解决方案

You can use backwards relationships.

{% for item in ingrcat %}
<h2>{{ item.name }}</h2>
<ul>
    {% for ingr in item.ingredience_set.all %}
    <li><a href="#" id="i{{ ingr.id }}">{{ ingr.name }}</a></li>
    {% endfor %}
</ul>
{% endfor %}

See documentation:

https://docs.djangoproject.com/en/dev/topics/db/queries/#following-relationships-backward

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