Limit choices to

Question

I have a model named Project which has a m2m field users. I have a task model with a FK project. And it has a field assigned_to. How can i limit the choices of assigned_to to only the users of the current project?

Answer 1

You need to create a custom form for the admin.

Your form should contain a ModelChoiceField in which you can specify a queryset parameter that defines what the available choices are. This form can be a ModelForm.

(the following example assumes users have an FK to your Project model)

forms.py

from django import forms

class TaskForm(forms.ModelForm):
    assigned_to = forms.ModelChoiceField(queryset=Users.objects.filter(user__project=project))

    class Meta:
        model = Task

Then assign the form to the ModelAdmin.

admin.py

from django.contrib import admin
from models import Task
from forms import TaskForm

class TaskAdmin(admin.ModelAdmin):
    form = TaskForm
admin.site.register(Task, TaskAdmin)

Answer 2

You could do this another way, using this nifty form factory trick.

def make_task_form(project):
    class _TaskForm(forms.Form):
        assigned_to = forms.ModelChoiceField(
              queryset=User.objects.filter(user__project=project))

        class Meta:
            model = Task
    return _TaskForm

Then from your view code you can do something like this:

project = Project.objects.get(id=234)
form_class = make_task_form(project)
...
form = form_class(request.POST)