Get type of Django form widget from within template

问题

I'm iterating through the fields of a form and for certain fields I want a slightly different layout, requiring altered HTML.

To do this accurately, I just need to know the widget type. Its class name or something similar. In standard python, this is easy! field.field.widget.__class__.__name__

Unfortunately, you're not allowed access to underscore variables in templates. Great!

You can test field.field.widget.input_type but this only works for text/password <input ../> types. I need more resolution that that.

To me, however difficult it might look, it makes most sense to do this at template level. I've outsourced the bit of code that handles HTML for fields to a separate template that gets included in the field-loop. This means it is consistent across ModelForms and standard Forms (something that wouldn't be true if I wrote an intermediary Form class).

If you can see a universal approach that doesn't require me to edit 20-odd forms, let me know too!

回答1:

As of Django 1.11, you can just use widget.input_type. Example:

{% for field in form.visible_fields %}
    <input type="{{ field.field.widget.input_type }}"
           id="{{ field.id_for_label }}"
           name="{{ field.html_name }}"
           placeholder="{{ field.label }}"
           maxlength="{{ field.field.max_length }}" />
{% endfor %}

回答2:

Making a template tag might work? Something like field.field.widget|widget_type

Edit from Oli: Good point! I just wrote a filter:

from django import template
register = template.Library()

@register.filter('klass')
def klass(ob):
    return ob.__class__.__name__

And now {{ object|klass }} renders correctly. Now I've just got to figure out how to use that inside a template's if statement.

Edit from Oli #2: I needed to use the result of that in an if statetement in-template, so I just shifted all that logic into the templatetag. Magic. Thanks for poking me in the right direction.

回答3:

Following up on the accepted answer - the enhanced if tag in Django 1.2 allows you to use filters in if tag comparisons. So you could now do your custom html/logic in the template like so:

<ul>
{% for field in form.fields %}
  <li>
    {% if field.field.widget|klass == "Textarea" %}
    <!-- do something special for Textarea -->
    <h2>Text Areas are Special </h2>
    {% else %}      
      {{ field.errors }}
      {{ field.label_tag }}
      {{ field }}
    {% endif %}

  </li>
{% endfor %}
</ul>

回答4:

Following the answer from Oli and rinti: I used this one and I think it is a bit simpler:

template code: {{ field|fieldtype }}

filter code:

from django import template
register = template.Library()

@register.filter('fieldtype')
def fieldtype(field):
    return field.field.widget.__class__.__name__

回答5:

Perhaps worth pointing out to contemporary readers that django-widget-tweaks provides field_type and widget_type template filters for this purpose, returning the respective class names in lowercase. In the example below I also show the output of the input_type property on the field widget (since Django 1.11), which may also be useful.

forms.py:

class ContactForm(forms.Form):
    name = forms.CharField(
        max_length=150,
        required=True,
        label='Your name'
    )

template.html:

{% load widget_tweaks %}

{% for field in form.visible_fields %}
{{ field.label }}
{{ field.field.widget.input_type }}
{{ field|field_type }}
{{ field|widget_type }})
{% endfor %}

Result:

Your name
text
charfield
textinput

Between these various options you should be able to find the right property to target for just about any use-case. If you need to capture the output of one of these filters for use in if statements, you can use the with template tag.

来源：https://stackoverflow.com/questions/1809874/get-type-of-django-form-widget-from-within-template

标签

django

django-templates

django-forms