Question

I’d like to create widgets that add specific classes to element markup when the associated field has errors.

I’m having a hard time finding information on how to check whether a field has errors associated with it, from within widget definition code.

At the moment I have the following stub widget code (the final widget will use more complex markup).

from django import forms
from django.utils.safestring import mark_safe
class CustomTextWidget(forms.Widget):
        def render(self, name, value, attrs):
            field_has_errors=False # change to dynamically reflect field errors, somehow
            if field_has_errors:
                error_class_string="error"
            else:
                error_class_string="" 
            return mark_safe(
            "<input type=\"text\" class=\"%s\" value=\"%s\" id=\"id_%s\" name=\"%s\">" % (error_class_string, value, name, name)
            )

Can anyone shed light on a sensible way to populate the field_has_errors Boolean here? (or perhaps suggest a better way to accomplish what I’m trying to do). Thanks in advance.

Answer 1

As Jason says, the widget has no access to the field itself. I think a better solution though is to use the cascading nature of CSS.

{% for field in form %}
<div class="field{% if field.errors %} field_error{% endif %}">
{{ field }}
</div>
{% endfor %}

Now in your CSS you can do:

div.field_error input { color: red }

or whatever you need.