Question

I want to load in a MultipleChoiceField as initial data a field with a manytomany relation, after save it.

My classes

class Course(models.Model):
    name = models.CharField(max_length=30)
    description = models.TextField(max_length=30)
    owner = models.ForeignKey(User)

class UserProfile(models.Model):
    user = models.OneToOneField(User, unique=True)
    status = models.CharField(max_length=10, choices=STATUS_CHOICES, default='student')
    courses_list = models.ManyToManyField(Course, blank=True)

My form

class AddSubscibeForm(forms.ModelForm):
    userprofile_set = forms.ModelMultipleChoiceField(initial = User.objects)
    class Meta:
        model = Course

My view

def addstudents(request, Course_id):
    editedcourse = Course.objects.get(id=Course_id)  # (The ID is in URL)
    form = AddSubscibeForm(instance=editedcourse)
    return render(request, 'addstudents.html', locals())

Actually, I have a multiplechoicelist with users, but i don’t have the list of users that have the course in their ‘courses_list’ field..

I can access to the user’s cours_list by a :

> editedcourse = Course.objects.get(id=Course_id)
> subscribed = editedcourse.userprofile_set.all()
> subscribed.user.username

If you have an idea.. 🙂

Answer 1

To confirm what you’re asking. You want to be able to see a form with a Course and choose which Users have that course in their courses?

You will NOT be able to properly use a field in a ModelForm that does not exist in its Model.

What you can do is change the model and have a ManyToManyField pointing both ways and then use the following:

class AddSubscibeForm(forms.ModelForm):
    class Meta:
        model = Course
        fields = ('userProfiles')

This would work assuming you have a ManyToManyField in Courses called userProfiles.

To get the ManyToManyField to work both ways, take a look at this ticket.

I haven’t tried this but I think it should work.

class Test1(models.Model):
    tests2 = models.ManyToManyField('Test2', blank=True)

class Test2(models.Model):
    tests1 = models.ManyToManyField(Test1, through=Test1.tests2.through, blank=True)

or this:

class User(models.Model):
    groups = models.ManyToManyField('Group', through='UserGroups')

class Group(models.Model):
    users = models.ManyToManyField('User', through='UserGroups')

class UserGroups(models.Model):
    user = models.ForeignKey(User)
    group = models.ForeignKey(Group)

    class Meta:
        db_table = 'app_user_groups'
        auto_created = User

Both of the above should work. And in both cases you shouldn’t have to change anything in the database.