How to pass type arguments when using a django generic class based view?

Question

I want to use django.views.generic.edit.FormView and since it's a generic, I'm giving it a type argument (MyForm):

class MyView(FormView[MyForm]):
    ...

But it causes this error:

TypeError: 'type' object is not subscriptable

What's the proper way to pass type arguments to FormView?

h33925 · Accepted Answer · 2022-09-09 09:14:26Z

1

You have two options (or three, if you include ignoring the error in mypy)

Monkeypatching

Monkeypatch the classes at runtime by putting

import django_stubs_ext

django_stubs_ext.monkeypatch()

in your <mysite>/settings.py file

if typing.TYPE_CHECKING:
  MyFormView = FormView[MyForm]
else:
  MyFormView = FormView

class MyView(MyFormView)):
  ...

this means you don't need django-stubs-ext as a runtime dependency.

answered Sep 6, 2022 at 13:31

h33925

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I used the second approach: "TypeAlias behind TYPE_CHECKING guard" and it worked! thanks.