Question

class Test(forms.Form):

    def set_choices(self, choices):
        self.choices = choices

    def get_choices(self):
        return self.choices

    options  = forms.ChoiceField(choices=get_choices())

f = Test()
f.set_choices(...)

Why isn’t this possible?
How else can I achieve the goal of passing data into class Test?
Thanks in advance.

Answer 1

This is a basic Python issue. You need to think about the order these commands are executed in, and their scope.

First, you define a form class called Test. That class has three attributes: a set_choices method, a get_choices method, and an options field. These definitions are evaluated when the class itself is defined. The definition of options calls get_choices(). However, there is no get_choices method in scope at that point, because the class is not yet defined.

Even if you somehow managed to sort out the scope issue, this would still not do what you want, because the definition of choices for options is done at define time. Even if you later call set_choices, options still has the value of get_choices that was returned when the field was defined.

So, what do you actually want to do? It seems like you want to set dynamic choices on the options field. So, you should override the __init__ method and define them there.

class Test(forms.Form):
    options = forms.ChoiceField(choices=())

    def __init__(self, *args, **kwargs):
        choices = kwargs.pop('choices', None)
        super(Test, self).__init__(*args, **kwargs)
        if choices is not None:
            self.fields['options'].choices = choices