Django DetailView get_context_data

Question

I'm new in Django. There is a html page (project_details) which should show the title and the tasks of the project, but shows only the title of the project, not the tasks. The tasks exists, the problem is the filter!!!

views.py The error is here

from .models import Project,Task
from django.views.generic import ListView, DetailView

class ProjectsList(ListView):
  template_name = 'projects_list.html'
  queryset= Project.objects.all()

class ProjectDetail(DetailView):
  model = Project
  template_name = 'projects_details.html'

  def get_context_data(self, **kwargs):
    context = super(ProjectDetail, self).get_context_data(**kwargs)
    ## the context is a list of the tasks of the Project##
    ##THIS IS THE ERROR##
    context['tasks'] = Task.object.filter(list=Project) <---->HERE ((work with Task.object.all() ))

    return context

models.py

class Project(models.Model):
   title = models.CharField(max_length=30)
   slug = AutoSlugField(populate_from='title', editable=False, always_update=True)

class Task(models.Model):
  title = models.CharField(max_length=250)
  list = models.ForeignKey(Project)
  slug = AutoSlugField(populate_from='title', editable=False, always_update=True)

urls.py

from django.conf.urls import url
from .models import Project
from .views import  ProjectsList, ProjectDetail

urlpatterns = [
   url(r'^$', ProjectsList.as_view(), name='project_list'),
   url(r'(?P<slug>[\w-]+)/$',ProjectDetail.as_view() , name='project_details'),]

projects_details.html

{% extends './base.html' %}
{% block content %}

<div>
<a href={{ object.get_absolute_url }}>
<h4> {{object.title}} </h4>
</a>
<ul>
{% for task in tasks %} <----> NO OUTPUT <li>
<li> {{task}}</li>
{% endfor %}
</ul>
</div>
{% endblock content %}

Sorry for my bad English.

Answer 1

Project is the model class, so doing (list=Project) doesn't make sense.

If you want to access the object in the detail view's get_context_data method, you can use self.object :

def get_context_data(self, **kwargs):
    context = super(ProjectDetail, self).get_context_data(**kwargs)
    context['tasks'] = Task.objects.filter(list=self.object)
    return context

However, you don't actually have to override the get_context_data method at all. In your template, you can follow the relationship backwards from a project to get its tasks:

{% for task in object.task_set.all %}
  <li>{{task}}</li>
{% endfor %}