Thanks Daniel. Both your proposed solutions worked very well. For now, I don't have other information stuffed into my model definitions, so the urls.py approach could do. However, if I decide to put more information into models.py, the def dispatch() approach could be useful.
One question though: Do I understand correctly, that your version of def dispatch() overwrites the Django dispatch method from UpdateView. As far as I can see, it checks the validity of the request method. Could I use def __init__ instead of def dispatch thanks + cheers, Mikkel From https://ccbv.co.uk/projects/Django/2.0/django.views.generic.edit/UpdateView/ def dispatch(self, request, *args, **kwargs): # Try to dispatch to the right method; if a method doesn't exist, # defer to the error handler. Also defer to the error handler if the # request method isn't on the approved list. if request.method.lower() in self.http_method_names: handler = getattr(self, request.method.lower(), self. http_method_not_allowed) else: handler = self.http_method_not_allowed return handler(request, *args, **kwargs) onsdag den 6. juni 2018 kl. 16.12.06 UTC+2 skrev Daniel Germano Travieso: > > Ok! I think I see your problem. > > It is a deeper understanding of python classes that may be the problem. > You see, "model" and "self" are class atributes of the python class that > houses your class based view (as every class in django is first a python > class). > > So, if you try to access the attribute "model" of the class, or the > attribute "self", a attribute that houses the instance of the class, on > it's class attributes definitions you will have problems, as the python > interpreter only load these modules lazyly, not actually going through on > finding the value for the attribute you referenced. > > One solution is to have that value (for the attribute "field" as a > @property that is a function that then the python interpreter will go > through and execute the reference lookup. > > Another solution is to set that value to be initially None, and set the > value for the fields on the dispatch method of the view, something like > class ItemUpdateView(UpdateView): > template_name="foo.html" > fields = None > > def dispatch (self, request, *args, **kwargs): > self.fields = self.model.fields > return super(ItemUpdateView, self).dispatch(request, *args, **kwargs) > > > > But as of my understanding of your problem, you are trying to just > customize which form fields to display to the user based on which model the > user is updating, so you could just specify the form_class attribute on the > path (just as you did with the model). > > Hope it helps! > > > On Wed, Jun 6, 2018, 10:36 Mikkel Kromann <[email protected] > <javascript:>> wrote: > >> Hello Daniel. >> >> Thank you for your reply. Perhaps I was not explicit enough in describing >> my problem - it is far simpler than your solution indicates. >> In my model definitions, I already have a list of the fields to be >> represented in the form of UpdateView - it is an attribute in the form of a >> simple array called "fields". >> I don't want UpdateView to make a form for all columns of the model's >> data table, just the fields from my custom array in the Model objects. >> >> My problem is simply: How to access my custom attribute "field" in the >> Model attribute passed to the Class Based View function. >> As described, I get compilation errors, complaining that "model" and >> "self" are names not defined. >> From the documentation (and my so far not too great Python understandign) >> it is not clear to me whether "Model" is simply the name of the model, or >> if it is the entire Model object instance. >> >> >> thanks again, Mikkel >> >> >> onsdag den 6. juni 2018 kl. 15.01.05 UTC+2 skrev Daniel Germano Travieso: >>> >>> Hello! >>> >>> As you see on the documentation ( >>> https://docs.djangoproject.com/en/2.0/topics/class-based-views/) for >>> the class based views, any arguments you pass to the class based view >>> .as_view() method will override attributes of the class based view, so if >>> you set MyCView.as_view(model=Foo) is the same as setting class MyCView: >>> model=Foo directly. >>> >>> Now to access the field names of the Model, you used to be able to call >>> a .get_field_names() or something like that but that is depreciated since >>> 1.10. Now to do that you should use the Model._meta to get_fields(). Check >>> the documentation for the Model._meta to check its full potential. >>> >>> Hope it helps! >>> >>> On Wed, Jun 6, 2018, 07:33 Mikkel Kromann <[email protected]> >>> wrote: >>> >>>> Thanks for the advice, Andréas. >>>> But the response is the same: >>>> >>>> File "C:\Users\ ... xxxxxxx ... \items\views.py", line 7, in >>>> ItemUpdateView >>>> fields = self.model.fields >>>> NameError: name 'self' is not defined >>>> >>>> >>>> >>>> As far as I understood, model is an attribute, not a method (though I'm >>>> new to Python and Django, so I'm unsure about this). >>>> Does attribute/method make a difference in this case? >>>> >>>> cheers, Mikkel >>>> tirsdag den 5. juni 2018 kl. 22.10.31 UTC+2 skrev Andréas Kühne: >>>>> >>>>> Hi, >>>>> >>>>> Have you tried self.model? It should be present in all methods in the >>>>> class? >>>>> >>>>> Regards, >>>>> >>>>> Andréas >>>>> >>>>> 2018-06-05 21:56 GMT+02:00 Mikkel Kromann <[email protected]>: >>>>> >>>>>> Dear Django-users. >>>>>> >>>>>> I'm slowly working towards a Django "data-warehouse" framework, where >>>>>> I can easily add a lot of models (each containing a table with data), >>>>>> while >>>>>> sticking to only few reusable views. >>>>>> >>>>>> I've realised that in urls.py, it is possible to specify the model on >>>>>> which the UpdateView is going to do its magic. >>>>>> This allows me to use a generic UpdateView (which I called >>>>>> ItemUpdateView) and template for all my models, which will save me a ton >>>>>> of >>>>>> almost identical lines of code. >>>>>> >>>>>> However, in the generic ItemUpdateView, I of course need to specify >>>>>> the fields of the specific model chosen in urls.py. >>>>>> As I ideally only want a few generic views (i.e. ItemCreateView, >>>>>> ItemUpdateView, ItemDeleteView and ItemListView), I've chosen to place >>>>>> the >>>>>> field array in my model definition, hoping to be able to access it from >>>>>> my >>>>>> generic Class Based Views >>>>>> >>>>>> But how do I access the model attribute in (Item)UpdateView >>>>>> >>>>>> >>>>>> thanks, Mikkel >>>>>> >>>>>> From views.py >>>>>> from django.views.generic import CreateView, ListView, UpdateView, >>>>>> DeleteView >>>>>> >>>>>> class ItemUpdateView(UpdateView): >>>>>> template_name = "item_form.html" >>>>>> # How do I access the model attribute of ItemUpdateView as given in >>>>>> urls.py? >>>>>> # This line below returns the error "NameError: name 'model' not >>>>>> defined" >>>>>> fields = model.fields >>>>>> >>>>>> From urls.py >>>>>> from django.urls import path >>>>>> from . views import ItemUpdate >>>>>> from . models import Region, Location >>>>>> >>>>>> # Awesome! I can specify the model to be used by ItemUpdateView >>>>>> urlpatterns = [ >>>>>> path('update/region/<pk>', ItemUpdateView.as_view(model=Region >>>>>> ), name='region_update'), >>>>>> path('update/location/<pk>', ItemUpdateView.as_view(model= >>>>>> Location), name='location_update'), >>>>>> ] >>>>>> >>>>>> >>>>>> >>>>>> From models.py (Region and Location are only two of my tables, I'd >>>>>> like to have say 20 or 30 models >>>>>> from django.db import models >>>>>> >>>>>> # Abstract class for our items including common methods, data and >>>>>> definitions >>>>>> class ItemModel(models.Model): >>>>>> >>>>>> fields = [ 'label', 'short', 'descr' ] >>>>>> label = models.CharField(max_length=10) >>>>>> short = models.CharField(max_length=15) >>>>>> descr = models.CharField(max_length=40) >>>>>> >>>>>> def __str__(self): >>>>>> return self.short >>>>>> >>>>>> class Meta: >>>>>> abstract = True >>>>>> >>>>>> class Region(ItemModel): >>>>>> fields = [ 'label', 'short', 'descr' ] >>>>>> >>>>>> class Location(ItemModel): >>>>>> fields = [ 'label', 'short', 'descr', 'region' ] >>>>>> region = models.ForeignKey(Region, on_delete=models.CASCADE) >>>>>> >>>>>> class Plant(ItemModel): >>>>>> fields = [ 'label', 'short', 'descr', 'location', 'capex', >>>>>> 'opex', 'capacity' ] >>>>>> location= models.ForeignKey(Location, on_delete=models.CASCADE) >>>>>> capex = models.DecimalField(decimal_places=3, max_digits=8) >>>>>> opex = models.DecimalField(decimal_places=3, max_digits=8) >>>>>> capacity= models.DecimalField(decimal_places=3, max_digits=8) >>>>>> >>>>>> >>>>>> -- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "Django users" group. >>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>> send an email to [email protected]. >>>>>> To post to this group, send email to [email protected]. >>>>>> Visit this group at https://groups.google.com/group/django-users. >>>>>> To view this discussion on the web visit >>>>>> https://groups.google.com/d/msgid/django-users/ec4634e5-2279-49a7-9045-21712de87584%40googlegroups.com >>>>>> >>>>>> <https://groups.google.com/d/msgid/django-users/ec4634e5-2279-49a7-9045-21712de87584%40googlegroups.com?utm_medium=email&utm_source=footer> >>>>>> . >>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>> >>>>> >>>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "Django users" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> To post to this group, send email to [email protected]. >>>> Visit this group at https://groups.google.com/group/django-users. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/django-users/95db9cca-58ca-4460-ae39-9150bb199bff%40googlegroups.com >>>> >>>> <https://groups.google.com/d/msgid/django-users/95db9cca-58ca-4460-ae39-9150bb199bff%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "Django users" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected] <javascript:>. >> To post to this group, send email to [email protected] >> <javascript:>. >> Visit this group at https://groups.google.com/group/django-users. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/django-users/c857567f-dd71-46c1-a05b-787566bfa180%40googlegroups.com >> >> <https://groups.google.com/d/msgid/django-users/c857567f-dd71-46c1-a05b-787566bfa180%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > -- You received this message because you are subscribed to the Google Groups "Django users" group. 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