Django和AJAX形式

I have a django modelform that I have setup to use jQuery and the jQuery AjaxForm plugin.

It quite correctly processes any data submitted and either shows errors or saves, however it simply will not repopulate the form with refreshed data post successful submit.

Here is my code:

@login_required
@transaction.commit_on_success
def edit(request, pk):
    a = get_object_or_404(Item.objects.select_related(), pk=pk)
    b = Status.objects.all() # was select_related()
    currentsec = a.integrity_hash
    item_ct = ContentType.objects.get_for_model(Item).id

    try:
        last_viewed = request.session['last_viewed']
        if pk not in last_viewed:
                if len(last_viewed) > 19:
                        last_viewed.pop(0)        
                last_viewed.append(pk)
        request.session['last_viewed'] = last_viewed
    except KeyError:
        request.session['last_viewed'] = [pk]

    if request.method == 'POST':
        f = ItemForm(request.POST, instance=a)
        if f.is_valid():
            editted_item = f.save(commit=False)
            # check for changes to item before save
            if currentsec == editted_item.integrity_hash:
                editted_item.integrity_hash = form_hmac(f)
                # lock item row for updating
                Item.objects.select_for_update().filter(pk=pk)
                editted_item.save()

                m = Modification.objects.create(
                    content_object = a,
                    object_id = pk,
                    action = 1,
                    modifier = request.user,
                    )
                m.save()

                messages.success(request, 'Item editted successfully.')

                if request.is_ajax():
                    response_dict = serialize('json', (editted_item,))
                else:
                    return HttpResponseRedirect(reverse('edit', kwargs={'pk': pk,}))
            else:
                messages.error(request, 'Item could not be saved. It has been modified whilst you were working on it.')
                response_dict = json.dumps({'errors': dict([(k, [unicode(e) for e in v]) for k,v in f.errors.items()])})
        else:
            messages.error(request, 'Item could not be saved.')
            response_dict = json.dumps({'errors': dict([(k, [unicode(e) for e in v]) for k,v in f.errors.items()])})
    else:
        f = ItemForm(instance=a)
        f.fields["item_maker"].queryset = ItemMaker.objects.filter(Q(end_date__isnull=True) | Q(pk = a.item_maker.id) | Q(end_date__gte=a.date_due))

    variables = RequestContext(request, {
        'item': a,
        'form': f,
        'itemstatus': b,
        'item_ct': item_ct,
    })

    if request.is_ajax():
        return HttpResponse(response_dict, mimetype="application/json")

    return render_to_response('items/item_edit.html', variables)