How to show related items using DeleteView in Django?

Question

I am doing a view to delete (using the generic view DeleteView from Django) an instance from a model, but it cascades and deletes instances from other models:

Answer 1

I use a cutdown modifcation of get_deleted_objects() from the admin and use it to extend my context in get_context in the delete view:

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

  {% for model_name, object_count in model_count %}
    
  {% endfor %}

  

    
Name
    
Amount
  

      
{{ model_name|capfirst }}
      
{{ object_count }}
    

  

    {{ deletable_objects|unordered_list }}
  

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