Django - Mixing ListView and CreateView

问题

I'm want to create one page with a form, and every time I submit the form it adds an item to the list below the form.

I can make it work using 2 pages:

one page using the mixin CreateView to add items
one page ListView to have the list.

But I'm trying to have the form and the list on the same page. So I tried to create a class with both mixin:

class FormAndListView(ListView, CreateView):
    pass

Then I've used this class:

FormAndListView.as_view(
    queryset=PdfFile.objects.order_by('id'),
    context_object_name='all_PDF',
    success_url = 'listview',
    form_class = UploadFileForm,
    template_name='textfrompdf/index.html',)),

But when I try to load the page, I get the error: Exception Value: 'FormAndListView' object has no attribute 'object'

Traceback:
File "C:\Program Files\Python_2.7\lib\site-packages\django\core\handlers\base.py" in get_response
  111.                         response = callback(request, *callback_args, **callback_kwargs)
File "C:\Program Files\Python_2.7\lib\site-packages\django\views\generic\base.py" in view
  47.             return self.dispatch(request, *args, **kwargs)
File "C:\Program Files\Python_2.7\lib\site-packages\django\views\generic\base.py" in dispatch
  68.         return handler(request, *args, **kwargs)
File "C:\Program Files\Python_2.7\lib\site-packages\django\views\generic\list.py" in get
  122.         return self.render_to_response(context)
File "C:\Program Files\Python_2.7\lib\site-packages\django\views\generic\base.py" in render_to_response
  94.             template = self.get_template_names(),
File "C:\Program Files\Python_2.7\lib\site-packages\django\views\generic\list.py" in get_template_names
  134.             names = super(MultipleObjectTemplateResponseMixin, self).get_template_names()
File "C:\Program Files\Python_2.7\lib\site-packages\django\views\generic\detail.py" in get_template_names
  122.         if self.object and self.template_name_field:

Exception Type: AttributeError at /PDF/
Exception Value: 'FormAndListView' object has no attribute 'object'

I've no idea how to debug that. Where to start?

回答1:

I use a lot of views that involve a form and a list of objects. Rather than trying to mixin things I just add the queryset into the context data as below.

class UploadFileView(CreateView):
    form_class = UploadFileForm
    success_url = 'listview'
    template_name = 'textfrompdf/index.html'

    def get_context_data(self, **kwargs):
        kwargs['object_list'] = PdfFile.objects.order_by('id')
        return super(UploadFileView, self).get_context_data(**kwargs)

回答2:

Do not mix list and update views.
Instead, create two separate views for these tasks:

List view displays the list and a web form with action URL pointing to the create view.
Create view accepts POST data and

displays form with error message in case of failure;
redirects to the list view in case of success.

Also I've tried to use class-based views and found that they are too complex.
I think it is much easier to use old-style function views.

回答3:

I found the answer, there is 2 problems:

ListView and CreateView are "high level" mixin which aggregate "lower level" mixins. But these lower level mixins are not compatible together.
The View class calls directly the render_to_response(), but in my scenario, there is 2 view class and render_to_response() should only be called once at the end.

I was able "solve" this issue using the following steps:

Instead of calling ListView and CreateView, I used lower level mixins. Moreover I called explicitly BaseCreateView and BaseListView from which I "extracted" the form and object_list

class FormAndListView(BaseCreateView, BaseListView, TemplateResponseMixin):
    def get(self, request, *args, **kwargs):
        formView = BaseCreateView.get(self, request, *args, **kwargs)
        listView = BaseListView.get(self, request, *args, **kwargs)
        formData = formView.context_data['form']
        listData = listView.context_data['object_list']
        return render_to_response('textfrompdf/index.html', {'form' : formData, 'all_PDF' : listData},
                           context_instance=RequestContext(request))

It's not clean but it works!

回答4:

I have made my own class to solve this problem. I don't know if it's better or worse, but it works too. I have tried to use the generic mixins and have tested that validation and pagination work.

The code in GitHub

class ListAppendView(MultipleObjectMixin,
    MultipleObjectTemplateResponseMixin,
    ModelFormMixin,
    ProcessFormView):
    """ A View that displays a list of objects and a form to create a new object.
    The View processes this form. """
    template_name_suffix = '_append'
    allow_empty = True

    def get(self, request, *args, **kwargs):
        self.object_list = self.get_queryset()
        allow_empty = self.get_allow_empty()
        if not allow_empty and len(self.object_list) == 0:
            raise Http404(_(u"Empty list and '%(class_name)s.allow_empty' is False.")
                          % {'class_name': self.__class__.__name__})
        self.object = None
        form_class = self.get_form_class()
        form = self.get_form(form_class)
        context = self.get_context_data(object_list=self.object_list, form=form)
        return self.render_to_response(context)

    def post(self, request, *args, **kwargs):
        self.object = None
        return super(ListAppendView, self).post(request, *args, **kwargs)

    def form_invalid(self, form):
        self.object_list = self.get_queryset()
        return self.render_to_response(self.get_context_data(object_list=self.object_list, form=form))

If you try it and find any errors, please tell me here or in GitHub.

来源：https://stackoverflow.com/questions/9338181/django-mixing-listview-and-createview

标签

django

listview

mixins