I am trying to realize a Class Based ListView
which displays a selection of a table set. If the site is requested the first time, the dataset should be displayed. I would prefer a POST submission, but GET is also fine.
That is a problem, which was easy to handle with function based views
, however with class based views I have a hard time to get my head around.
My problem is that I get a various number of error, which are caused by my limited understanding of the classed based views. I have read various documentations and I understand views for direct query requests, but as soon as I would like to add a form to the query statement, I run into different error. For the code below, I receive an ValueError: Cannot use None as a query value
.
What would be the best practise work flow for a class based ListView depending on form entries (otherwise selecting the whole database)?
This is my sample code:
models.py
class Profile(models.Model):
name = models.CharField(_('Name'), max_length=255)
def __unicode__(self):
return '%name' % {'name': self.name}
@staticmethod
def get_queryset(params):
date_created = params.get('date_created')
keyword = params.get('keyword')
qset = Q(pk__gt = 0)
if keyword:
qset &= Q(title__icontains = keyword)
if date_created:
qset &= Q(date_created__gte = date_created)
return qset
forms.py
class ProfileSearchForm(forms.Form):
name = forms.CharField(required=False)
views.py
class ProfileList(ListView):
model = Profile
form_class = ProfileSearchForm
context_object_name = 'profiles'
template_name = 'pages/profile/list_profiles.html'
profiles = []
def post(self, request, *args, **kwargs):
self.show_results = False
self.object_list = self.get_queryset()
form = form_class(self.request.POST or None)
if form.is_valid():
self.show_results = True
self.profiles = Profile.objects.filter(name__icontains=form.cleaned_data['name'])
else:
self.profiles = Profile.objects.all()
return self.render_to_response(self.get_context_data(object_list=self.object_list, form=form))
def get_context_data(self, **kwargs):
context = super(ProfileList, self).get_context_data(**kwargs)
if not self.profiles:
self.profiles = Profile.objects.all()
context.update({
'profiles': self.profiles
})
return context
Below I added the FBV which does the job. How can I translate this functionality into a CBV? It seems to be so simple in function based views, but not in class based views.
def list_profiles(request):
form_class = ProfileSearchForm
model = Profile
template_name = 'pages/profile/list_profiles.html'
paginate_by = 10
form = form_class(request.POST or None)
if form.is_valid():
profile_list = model.objects.filter(name__icontains=form.cleaned_data['name'])
else:
profile_list = model.objects.all()
paginator = Paginator(profile_list, 10) # Show 10 contacts per page
page = request.GET.get('page')
try:
profiles = paginator.page(page)
except PageNotAnInteger:
profiles = paginator.page(1)
except EmptyPage:
profiles = paginator.page(paginator.num_pages)
return render_to_response(template_name,
{'form': form, 'profiles': suppliers,},
context_instance=RequestContext(request))
I think your goal is trying to filter queryset based on form submission, if so, by using GET :
class ProfileSearchView(ListView)
template_name = '/your/template.html'
model = Person
def get_queryset(self):
name = self.kwargs.get('name', '')
object_list = self.model.objects.all()
if name:
object_list = object_list.filter(name__icontains=name)
return object_list
Then all you need to do is write a get
method to render template and context.
Maybe not the best approach. By using the code above, you no need define a Django form.
Here's how it works : Class based views separates its way to render template, to process form and so on. Like, get
handles GET response, post
handles POST response, get_queryset
and get_object
is self explanatory, and so on. The easy way to know what's method available, fire up a shell and type :
from django.views.generic import ListView
if you want to know about ListView
and then type dir(ListView)
. There you can see all the method defined and go visit the source code to understand it. The get_queryset
method used to get a queryset. Why not just define it like this, it works too :
class FooView(ListView):
template_name = 'foo.html'
queryset = Photo.objects.all() # or anything
We can do it like above, but we can't do dynamic filtering by using that approach. By using get_queryset
we can do dynamic filtering, using any data/value/information we have, it means we also can use name
parameter that is sent by GET
, and it's available on kwargs
, or in this case, on self.kwargs["some_key"]
where some_key
is any parameter you specified