DJANGO: Add “select all” choice option to ModelMultipleChoiceField?

Question

Is there a way to add additional choices to a ModelMultipleChoiceField? Specifically, I want to add a "Select All" option instead of an End-User having to select all of the choices individually.

Current Model Form:

class QueryForm(forms.Form):
    book = forms.ModelMultipleChoiceField(queryset=Book.objects.all())

I want something like this:

class QueryForm(forms.Form):
    book = forms.ModelMultipleChoiceField(choices=(('Select All', 'Select All'),(Book.objects.all()))

How can I add the Select All option to Model Multiple Choice Field?

Answer 1

Is this in the Django admin or in your own form? If it's the admin, the easiest solution is to simply add the field to ModelAdmin.filter_horizontal or ModelAdmin.filter_vertical . The special field that the Django admin will use has a "Choose All" option builtin.

If it's your own form, JS is your best bet as @AdamKG recommends. Given the following:

<div class="field">
    <select multiple="multiple" name="my_field">
        <option value="something">Something</option>
        ...
    </select>
    <a href="#" class="select-all">Select All</a>
</div>

This bit of jQuery should do the trick:

$('.select-all').click(function(){
    $('option', $(this).parent()).attr('selected', 'selected');
});

Answer 2

You will need to convert your ModelMultipleChoiceField to a MultipleChoiceField that gets its choices from the related model in __init__() . Add a "Select All" option with a sentinel (eg "all") instead of the PK that you will get from the actual models. Then just detect this in the POST view and set things appropriately.