Django label_for_id on CheckboxSelectMultiple widget not showing

Question

I am trying to build a form containing a CheckboxSelectMultiple widget. When using the build-in rendering like so

{{ f.activities }}

I get the following result

<ul id="id_reviewitem_set-0-activities">
    <li>
        <label for="id_reviewitem_set-0-activities_0">
            <input type="checkbox" name="reviewitem_set-0-activities" value="1" id="id_reviewitem_set-0-activities_0" />
 Test
        </label>
    </li>
...

An ID is generated for the field as a whole (as seen in the ul tag) and for each individual option (as seen in the input tag). This is the result I would expect.

However, if I do the whole thing manually like so

<ul id="{{ f.activities.id_for_label }}">
{% for option in f.activities %}
    <li>
        {{ option }}
    </li>
{% endfor %}
</ul>

The ID for the activities field is not returned, so I get

<ul id="">
    <li>
        <label for="id_reviewitem_set-0-activities_0">
            <input type="checkbox" name="reviewitem_set-0-activities" value="1" id="id_reviewitem_set-0-activities_0" />
 Test
        </label>
    </li>
...

It would be useful for me to have the id as I am using it for some js stuff. Is it possible to access the id of the field (i.e. "id_reviewitem_set-0-activities") or do I need to create my own in the template?

Answer 1

as per the docs:

 The outer <ul> container receives the id attribute of the widget, if defined, or BoundField.auto_id otherwise.

thus you can get the id you're looking for like this:

<ul id="{{ f.activities.auto_id }}">
{% for option in f.activities %}
    <li>
        {{ option }}
    </li>
{% endfor %}
</ul>