Question

I’m trying to restrict the selectable values of a ‘persons’ field in a particular form.

I have a TaskPerson model that has two foreign keys: one for ‘task’ one for ‘person’.

In my form, the persons field should allow the user to select one or more persons, but only those persons which match a certain task.

I’ve attempted this:

persons = [tp.person for tp in TaskPerson.objects.filter(task=thistask)]    
form.fields["persons"].queryset = persons

This list comprehension gives me the correct person objects I require, but my form doesn’t display at all, presumably because it gives me only a standard python list.

I had a look over the docs, but I’m not quite sure how to progress. Could someone please advise how I can correctly display my form?

Many thanks

Answer 1

You can easily get a QuerySet of Person objects by following the reverse relationship to TaskPerson
http://docs.djangoproject.com/en/dev/topics/db/queries/#following-relationships-backward

form.fields['field'].queryset = Person.objects.filter(taskperson__task=thistask)