如何在Django中使用DeleteView显示相关项目？

Question

我正在做一个视图从模型中删除（使用Django的通用视图DeleteView）一个实例，但它从其他模型级联并删除实例：

url(r'^person/(?P<pk>\d+)/delete/$', login_required(DeleteView.as_view(model=Person, success_url='/person/', template_name='delete.html')), name='person_delete'),

我想要做的是显示将被删除的相关项目列表，如管理界面所做的那样，如：

Are you sure you are going to delete Person NAMEOFTHEPERSON?
By deleting it, you are also going to delete:
CLASSNAME1: CLASSOBJECT1 ; CLASSNAME2: CLASSOBJECT2 ; CLASSNAME3: CLASSOBJECT3 ; etc

Answer 1

您可以使用Django用于确定要在级联中删除的对象的Collector类。实例化它，然后在其上调用collect，传递您要删除的对象。它需要一个列表或查询集，所以如果你只有一个对象，只需放入一个列表：

from django.db.models.deletion import Collector

collector = Collector(using='default') # or specific database
collector.collect([some_instance])
for model, instance in collector.instances_with_model():
    # do something

instances_with_model返回一个生成器，因此您只能在循环的上下文中使用它。如果您更喜欢可以操作的实际数据结构，那么admin contrib包有一个名为Collector的NestedObjects子类，其工作方式相同，但有一个返回分层列表的nested方法：

from django.contrib.admin.utils import NestedObjects

collector = NestedObjects(using='default') # or specific database
collector.collect([some_instance])
to_delete = collector.nested()

更新：自Django 1.9以来，django.contrib.admin.util被重命名为django.contrib.admin.utils

Answer 2

更新：从Django 1.9+ NestedObject应该从django.contrib.admin.utils导入

    from django.contrib.admin.utils import NestedObjects

Answer 3

我使用来自管理员的get_deleted_objects（）的缩减修改，并使用它在删除视图中的get_context中扩展我的上下文：

define somewhere

from django.contrib.admin.utils import NestedObjects
from django.utils.text import capfirst
from django.utils.encoding import force_text

def get_deleted_objects(objs): 
    collector = NestedObjects(using='default')
    collector.collect(objs)
    #
    def format_callback(obj):
        opts = obj._meta
        no_edit_link = '%s: %s' % (capfirst(opts.verbose_name),
                                   force_text(obj))
        return no_edit_link            
    #
    to_delete = collector.nested(format_callback)
    protected = [format_callback(obj) for obj in collector.protected]
    model_count = {model._meta.verbose_name_plural: len(objs) for model, objs in collector.model_objs.items()}
    #
    return to_delete, model_count, protected

then in your views

from somewhere import get_deleted_objects
#
class ExampleDelete(DeleteView):
    # ...
    def get_context_data(self, **kwargs):
        #
        context = super().get_context_data(**kwargs)
        #
        deletable_objects, model_count, protected = get_deleted_objects([self.object])
        #
        context['deletable_objects']=deletable_objects
        context['model_count']=dict(model_count).items()
        context['protected']=protected
        #
        return context

now you can use them in your template

<table>
  <tr>
    <th>Name</th>
    <th>Amount</th>
  </tr>
  {% for model_name, object_count in model_count %}
    <tr>
      <td>{{ model_name|capfirst }}</td>
      <td>{{ object_count }}</td>
    </tr>
  {% endfor %}
</table>
<p>
  <ul>
    {{ deletable_objects|unordered_list }}
  </ul>
</p>

Most is just copy/paste/edit/delete unwanted from django admin