CODEWITHSUNDEEP
djangodjango-forms
Patrick Bassut
Patrick Bassut

Reputation: 3338

Dealing with model forms in Django

I thought it would be easier to start using models form instead of regular forms(giving up on all the easy things modelform provides). But when I try to do this:

>>> m = Model.objects.get(pk=1)
>>> f = ModelForm(instance=m)
>>> f.is_valid()
False
>>> f.save()
AttributeError: 'ModelForm' objects has no attribute 'cleaned_data'

I think django documentation is wrong by saying:

Every form produced by ModelForm also has a save() method. This method creates and saves a database object from the data bound to the form. A subclass of ModelForm can accept an existing model instance as the keyword argument instance; if this is supplied, save() will update that instance. If it’s not supplied, save() will create a new instance of the specified model

Cause this is just not working for me.

Am I right that the django documentation is wrong?

Thanks in advance.

Upvotes: 1

Views: 328

Answers (1)

mawimawi
mawimawi

Reputation: 4353

You may have forgotten to add "data" into the ModelForm instantiation according to the user's request.POST data.

f = ModelForm(data=request.POST, instance=m)
f.is_valid()  # is True if the data is ok.

In any case, it would be better to post your relevant code: The model class, the model form class and your view.

EDIT: you must add a data= parameter (or the first parameter, if you don't name it) to a ModelForm initialization, if you want is_valid() to work. is_valid is here to check the given data against the various validation rules, and only if it's ok, lets you save the ModelForm. Initializing a ModelForm just with the instance= named parameter does not trigger any validation, because there is nothing new to validate.

Upvotes: 5

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