Django: "Form object has no attribute..." error

Question

I'm new in Django ,and I'm trying to develop a simple Django application which takes two numbers from the user with a form and do some operation with those numbers and print the result with a Http Response. My code is the following:

forms.py

class SimpleForm(forms.ModelForm):

    a = forms.IntegerField(label='first' )
    b = forms.IntegerField(label='second' )

    def result(self):
        return doSomething(self.a, self.b)

views.py

class MainPage(FormView):
    template_name = 'simple.html'
    success_url = '/result/'
    form_class = SimpleForm

    def form_valid(self, form):
        return HttpResponse(form.result())

However, when I run this code on my localhost, it gives the error like

SimpleForm object has no attribute 'a'

So, what can be the problem? How can I get the user input in order to use it in my "result" function?

Thanks in advance...

falsetru · Accepted Answer · 2017-03-25 09:56:39Z

10

To access data, you need to use form.data:

def result(self):
    return doSomething(self.data['a'], self.data['b'])

If you called form.is_valid() before call result, you can also use cleaned_data. (Because OP is using FormView.form_valid, it is called automatically)

def result(self):
    return doSomething(self.cleaned_data['a'], self.cleaned_data['b'])

edited Mar 25, 2017 at 9:56

answered Mar 25, 2017 at 9:44

falsetru

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4 Comments

Wilfried Over a year ago

He call result() in form_valid(), so form.is_valid() was already call. Here it is preferable to only use cleaned_data to be sure about data verification, no?

falsetru Over a year ago

@Wilfried, You're right. I missed that. I'll mention that. Thank you for your comment.

Enes Altuncu Over a year ago

What is the difference between self.data and self.cleaned_data? I mean which one should I prefer?

falsetru Over a year ago

@qwerty, self.data returns raw data (strings), while self.cleaned_data returns converted data according to field type (int for the given case).

Wilfried · Accepted Answer · 2017-03-25 09:43:51Z

1

You form.a is an IntergerField(), not the result. You need to read cleaned_data dict of your form to access value of your form field. Cleaned_data documentation

class SimpleForm(forms.ModelForm):

    a = forms.IntegerField(label='first' )
    b = forms.IntegerField(label='second' )

    def result(self):
        return doSomething(self.cleaned_data['a'], self.cleaned_data['b'])

answered Mar 25, 2017 at 9:43

Wilfried

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