Question

I have been following this useful-looking article http://collingrady.wordpress.com/2008/02/18/editing-multiple-objects-in-django-with-newforms/. Unfortunately he doesn’t hint at the template code, so I’m guessing there.

I want to create a bunch of forms in a page, to add multiple objects to a model, with some common properties set by another form either in the page’s variables or at the top of the page. This is for a teacher’s marksheet.

My views.py:

def record_assessments(request, teachinggroup, objective):
    theclass = TeachingGroup.objects.get(name__iexact = teachinggroup)
    pupils = Pupil.objects.filter(teaching_group = theclass)
    theobjective = Objective.objects.get(code = objective)
    thedate = datetime.date.today()

    if request.method == 'POST':
        aforms = [PupilAssessmentForm(request.POST, prefix=x.id, instance=Assessment()) for x in pupils]
        if all(af.is_valid() for af in aforms):
            for af in aforms:
                new_record = af.save(commit = False)
                new_record.objective = theobjective
                new_record.date = thedate
                new_record.save()
            return redirect("/app/" + theclass + "/" + marksheet + "/" + theobjective.strand.code|lower + "/")
    else:
        aforms = [PupilAssessmentForm(prefix=str(x.id)) for x in pupils]
    return render_to_response('recordassessments.html', locals())

I haven’t managed to check the logic in the first if loop yet, as I haven’t managed to POST the form properly yet.

The page renders properly if I put

    else:
        aforms = [PupilAssessmentForm(prefix=str(x.id), instance=x) for x in pupils]

But then I’m tying a ModelForm from the Assessment model to an object in the Pupil model, which seems wrong.

My template:

{% for af in aforms %}
<form action="" method="post">
{{af.instance}}{{ af.errors }}
<p>
{{ af }}
{% endfor %}
<input type="submit" value="Submit">
</form>

The error (selected snippets):

Exception Type: TemplateSyntaxError
Exception Value:    Caught DoesNotExist while rendering:

error at line 20
Caught DoesNotExist while rendering: 
20    {% for af in aforms %}

And yet the aforms list appears in the page variables:

aforms  
[<two.app.forms.PupilAssessmentForm object at 0x21db0d0>,
 <two.app.forms.PupilAssessmentForm object at 0x21db650>]

Answer 1

I’m not sure why, but I managed to do it by changing the list to a dictionary, which suited my needs anyway for displaying the form as a table row per pupil together with some other assessment data. My original question remains open for anyone who knows an alternative method that more directly addresses the question I was originally asking, but here’s how I did it:

views.py (the relevant bits):

    if request.method == 'POST':
        assessment_grid = {}
        for x in pupils:
            form = PupilAssessmentForm(request.POST, prefix=str(x.id))
            try:
                assessment = Assessment.objects.filter(objective = theobjective).filter(pupil = x).filter(date__lte = thedate).latest('date')
            except Assessment.DoesNotExist:
                assessment = None
            pupil_row = [assessment, form]
            assessment_grid[x] = pupil_row
        if all(pupil_row[1].is_valid() for pupil, pupil_row in assessment_grid.items()):
            for pupil, pupil_row in assessment_grid.items():
                new_record = pupil_row[1].save(commit = False)
                new_record.objective = theobjective
                new_record.date = thedate
                new_record.teacher = theclass.teacher
                new_record.pupil = pupil
                new_record.save()
            return redirect("some link")
     else:
        assessment_grid = {}
        for x in pupils:
            form = PupilAssessmentForm(prefix=str(x.id))
            try:
                assessment = Assessment.objects.filter(objective = theobjective).filter(pupil = x).filter(date__lte = thedate).latest('date')
            except Assessment.DoesNotExist:
                assessment = None
            pupil_row = [assessment, form]
            assessment_grid[x] = pupil_row
    return render_to_response('recordassessments.html', locals())

I’m not sure whether there’s a more elegant way to assemble the dictionary, as mine isn’t particularly DRY. And I have no idea why I could unpack a dictionary containing a form yet not a list. Was my syntax wrong? Anyway: problem sorted; page renders.