Adding an "invalid" choice to a ChoiceField?

[Michael]

When specifying the choices parameter is there a way to mark say, for
example, the first choice as invalid?

e.g.

TOPIC_CHOICES = (
('erroneous', '-- pick one --'), # <-- I would not want this
choice to count as being valid
('general', 'General enquiry'),
('bug', 'Bug report'),
('suggestion', 'Suggestion'),
)

class ContactForm(forms.Form):
topic = forms.ChoiceField(choices=TOPIC_CHOICES)

The scenario I'm trying to address is I would like to prevent users
from skipping over a particular choice field (instead of the user
blindly accepting the first value in the list).

I'm curious how you guys would address this. Thanks!

[Thomas Guettler]

Michael schrieb:

> When specifying the choices parameter is there a way to mark say, for
> example, the first choice as invalid?
>
> e.g.
>
> TOPIC_CHOICES = (
> ('erroneous', '-- pick one --'), # <-- I would not want this
> choice to count as being valid
> ('general', 'General enquiry'),
> ('bug', 'Bug report'),
> ('suggestion', 'Suggestion'),
> )
>
> class ContactForm(forms.Form):
> topic = forms.ChoiceField(choices=TOPIC_CHOICES)
>

TOPIC_CHOICES=[('', '-- pick one --'), ('key1', '...'), ...]
And required=False for the ChoiceField (which is the default).

Thomas

--
Thomas Guettler, http://www.thomas-guettler.de/
E-Mail: guettli (*) thomas-guettler + de

[Michael]

> TOPIC_CHOICES=[('', '-- pick one --'), ('key1', '...'), ...]

Thanks, using an empty string for the value seems to do the trick. Is
there somewhere in the documentation that explains this behavior? I'm
not able to locate it anywhere.

> And required=False for the ChoiceField (which is the default).

Are you sure? the newforms documentation [1] seems to indicate that
required=True is the default for all Fields.

[1] http://www.djangoproject.com/documentation/newforms/#required

[alex....@gmail.com]

I assume he meant required=True, because being required is what causes
'' to not be allowed.

[Thomas Guettler]

Michael schrieb:

>> TOPIC_CHOICES=[('', '-- pick one --'), ('key1', '...'), ...]
>>
>
> Thanks, using an empty string for the value seems to do the trick. Is
> there somewhere in the documentation that explains this behavior? I'm
> not able to locate it anywhere.
>
>
>> And required=False for the ChoiceField (which is the default).
>>
>
> Are you sure? the newforms documentation [1] seems to indicate that
> required=True is the default for all Fields.
>

Sorry, this was a typo. required=True is the default.