displaying initial data in dropdown list in django - django

Question

I am writing an app in django1.4 to show the Lessons and Courses.I wanted to give an edit_lesson view in which the Course can be selected by the user.When the edit page is displayed,the Course associated with the Lesson should be shown as default selected.
I tried to write the view like this
def get_form_data(request):
return request.POST if request.method == 'POST' else None
def edit_lesson(request,id,template_name):
lesson = get_object_or_404(Lesson,pk=id,author=request.user)
form_data = get_form_data(request)
course_choices_form = CourseChoicesForm(form_data)
...
context = {'course_choices_form':course_choices_form,...}
if request.method == 'POST' and ....:
...
#if GET method ,display the form with initial data
course_choices_form = CourseChoicesForm(initial={'courseoption':lesson.course})
context.update({'course_choices_form':course_choices_form})
print "context['course_choices_form'].initial=",context['course_choices_form'].initial
return custom_render(request,context,template_name)
The CourseChoicesForm is like
class CourseChoicesForm(forms.Form):
courseoption = forms.ChoiceField(choices=[],required=False,label='Course')
def __init__(self, *args, **kwargs):
super(CourseChoicesForm, self).__init__(*args, **kwargs)
self.fields['courseoption'].choices = [(x.id,x.title) for x in Course.objects.all()]
In the edit_lesson template I am displaying the course_choices_form as
{{ course_choices_form.as_p}}
Still ,the drop down list does not show the lesson's course but just the first entry in the Course.objects.all()..
Can someone tell me what I am doing wrong?

Answer 1

Here's what I'm doing:
class CourseChoicesForm(forms.ModelForm):
courseoption = forms.ModelChoiceField(Courses.objects.all())
The Django engine take care for you of making the list of tuples to fill the ChoiceField. The Courses.objects.all() can be any queryset.
https://docs.djangoproject.com/en/dev/ref/forms/fields/#fields-which-handle-relationships