Re: How to use a DB table for choices=tuples in ChoiceField?

It looks like the Pythonic way is to create the list in

models.py and invoke it from forms.py.

Sorry about the heterogeneous names--some of 

them match the document the requirements were 

extracted from and others are more meaningful 

to me.  The former were picked because we'll 

need a requirements cross-reference and they'll 

be easier to match up with the requirements.  

And the dashes in place of spaces--most of the 

code examples I see here are almost unreadable 

because of leading spaces disappearing.  

I saw one example of replacing all but the last 

leading space with '-', and it was more readable.

Regards

On Fri, Jan 20, 2012 at 11:22 PM, Dennis Lee Bieber <wlfraed@ix.netcom.com> wrote:

On Fri, 20 Jan 2012 19:44:16 -0800 (PST), Bill Beal
<b.beal@eximflow.com> wrote:

       Caveat: I've only looked at Django, but not in enough detail to be
"expert"; my comments are based upon basic Python syntax/semantics (my
apologies to the developers, but I work better with printed
documentation and Django is too much of a moving target for the few
books that did come out to be relevant four months later)

>name 'scac_choicelist' is not defined at the marked
>line in my form:
>

       Which is true -- it is not defined at that point. (NOTE: your names
don't really help understanding the purpose of the variables <G>)

>from django import forms
>from django.forms.fields import ChoiceField
>from myapp.models import *
>
>BOL_CODE_QUALIFIERS = (
>  ('OB', 'Ocean Bill of Lading (OB)'),
>  ('BM', 'House Bill of Lading (BM)'),
>)
>
>class BolForm(forms.Form):
>- scac = forms.ChoiceField(
>----- label=u'Ocean Carrier',
>----- choices=scac_choicelist()) ######
>- bill_of_lading = forms.CharField(
>----- label=u'Bill of Lading #', max_length=50)
>- bol_type = forms.ChoiceField(
>----- label=u'Type of B/L',
>----- choices=BOL_CODE_QUALIFIERS)
>
>Here's my model:
>
>from django.db import models
>
>class Scac(models.Model):
>- code = models.CharField(max_length=4)
>- name = models.CharField(max_length=60)
>
>- def __unicode__(self):
>--- return self.code
>
>- def scac_choicelist():
>--- q = Scac.objects.all()
>--- scaclist = []
>--- for x in q:
>----- scaclist.append((x.code, x.name))
>----- return scaclist

       Presuming the many "-"s represent indentation, "scac_choicelist" is
a method of Scac. That means it should have at least one parameter: self

       def scac_choicelist(self):
               scaclist = []
               for item in self.objects.all():
                       scaclist.append((item.code, item.name))
               return scaclist

NOTE: based on your "-"s, your return statement is inside your loop, so
you'd be returning after processing only one element.

       NOW... In the form module you need to reference an instance of the
model! The method itself is not visible.

>- scac = forms.ChoiceField(
>----- label=u'Ocean Carrier',
>----- choices=scac_choicelist()) ######
>

Something like:

       scac = forms.ChoiceField(       label=u"Ocean Carrier",
                                                               choices=Scac().scac_choicelist())

--
       Wulfraed                 Dennis Lee Bieber         AF6VN
       wlfraed@ix.netcom.com    HTTP://wlfraed.home.netcom.com/

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