regroup formset

Say I have a formset that I'm passing to a template. Each form has a category field that I'd like to sort the formset by. This is the code that I have so far:

...
{% regroup formset by category as category_formset %}
<ul>
    {% for category in category_formset %}
    <li>{{ categor开发者_如何转开发y.grouper }}
        <ul>
            {% for form in category.list %}
            <li>{{ form.name.value }}</li>
            {% endfor %}
        </ul>
    </li>
    {% endfor %}
</ul>
...

The thing is that the output looks like:

• Category 1
  • ...
• Category 2
  • ...
• Category 2
  • ...
• Category 3
  • ...
• Category 3
  • ...
• Category 3
  • ...

That is, in the correct order, but not actually collated. I've already seen the "gotcha" here and tried adding {% regroup|dictsort:"category" ... %}, but that didn't help. Any ideas? Or is {% regroup %} not supported on formsets at all?

Update: I can get it to correctly collate the categories if I use {% regroup formset by category.value ... %}, but then it only displays integers (as category is a ForeignKey field). According to the docs it should be possible to use {% regroup formset by get_category_display ... %} to categorize on strings, but then regroup just returns None.

So I did get it to work, in the end. The trick was to use {% regroup formset by instance.category as category_list %}, which will display plaintext category names and collate the entries correctly.