Question

I need to make an automatic add in a ManyToMany field. My Class :

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)

After saving a new Course I want to add it to course_list of the user :

def newcourse(request):
if not request.user.is_authenticated():
    return render_to_response('login.html')
form = CourseForm()
if request.method == 'POST':
    form = CourseForm(request.POST)
    if form.is_valid():
        obj = form.save(commit=False)
        obj.owner = request.user
        obj = form.save()
        course_list = request.user.userprofile.courses_list.all()
        course_list += form
        course_list.save()
        return render(request, 'mycourses.html')
return render(request, 'newcourse.html', locals())

But it doesn’t works : `unsupported operand type(s) for +=: ‘ManyRelatedManager’ and ‘CourseForm’“

Maybe I need to make an new request ?

If you have an idea.. 😀

Answer 1

You need to do the following:

request.user.userprofile.courses_list.add(obj)

See the docs on ManyToMany relationships for more detail:

https://docs.djangoproject.com/en/dev/topics/db/examples/many_to_many/

Of course, you should probably handle getting the profile in the “proper” way as well:

try:
    profile = request.user.get_profile()
    profile.courses_list.add(obj)
except UserProfile.DoesNotExist:
    messages.error(request, "Couldn't find profile")