基于类的视图中的表单处理

Question

I have problem when form is not valid (in POST method).

didn't return an HttpResponse object. It returned None instead.

I could paste this line to last line of Post method

return render(request, self.template_name, context)

But context variable is initialized in Get method. How can I pass context to post method?

class EventPage(View):
    template_name = 'event.html'

    def get(self, request, event_id):
        event = Event.objects.get(id = event_id)
        participants = Participant.objects.filter(event_id = event.id)
        register_to_event_form = RegisterToEvent()
        context = {
            'register_to_event_form': register_to_event_form,
            'title': event.title,
            'description': event.description,
        }
        return render(request, self.template_name, context)

    def post(self, request, event_id):
        event = Event.objects.get(id = event_id)
        if request.method == "POST":
            register_to_event_form = RegisterToEvent(request.POST)
            if register_to_event_form.is_valid():
                participant = register_to_event_form.save(commit=False)
                participant.event = event
                participant.save()
                return HttpResponseRedirect('/event-%s' %event_id)

Answer 1

You should not be doing things this way at all. The whole point of the class-based views is that they provide a series of methods for you to override which are called by the default implementations of get and post ; you should not really be overriding get and post yourself.

In your case you should be using a CreateView, not a plain view. And you should be returning the events and participants in a get_context_data method. Setting the event property of the saved object should happen in the form_valid method.

Answer 2

我认为在返回HttpResponseRedirect的格式无效的情况下，您需要else语句

Answer 3

you are not returning anything if your form is invalid, so you can do like:

 def post(self, request, event_id):
    event = Event.objects.get(id = event_id)
    register_to_event_form = RegisterToEvent(request.POST)
    if register_to_event_form.is_valid():
        . . .      
        return HttpResponseRedirect('/event-%s' %event_id)
    else:
        context = {'register_to_event_form': register_to_event_form}
        return render(request, self.template_name, context)

and you dont need if request.method == "POST": in your post method