Argthtjtr

I am trying to customise a django form for use with bootstrap 4, custom html layout & per field class or id names on the FormModel defintion

I have the following html

{% for hidden_field in form.hidden_fields %}

    {{ hidden_field }}

{% endfor %}



{% if form.non_field_errors %}

    <div class="alert alert-danger" role="alert">

        {% for error in form.non_field_errors %}

            {{ error }}

        {% endfor %}

    </div>

{% endif %}



{% for field in form.visible_fields %}

    <div class="form-group">

        {{ field.label_tag }}

        {% if form.is_bound %}

            {% if field.errors %}

                {% render_field field class="form-control is-invalid" %}

                {% for error in field.errors %}

                    <div class="invalid-feedback">

                        {{ error }}

                    </div>

                {% endfor %}

            {% else %}

                {% render_field field class="form-control is-valid" %}

            {% endif %}

        {% else %}

            {% render_field field class="form-control" %}

        {% endif %}



        {% if field.help_text %}

            <small class="form-text text-muted">{{ field.help_text }}</small>

        {% endif %}

    </div>

{% endfor %}

And the following form defintion:

class DocumentForm(forms.ModelForm):

    field1 = PartLookupField(required=True, widget=forms.TextInput(attrs={'class': 'field1-choice-ajax'}))

    field2 = forms.CharField(required=True, widget=forms.TextInput(attrs={'id': 'field2-field'}))

    form_lines = forms.CharField(widget=forms.HiddenInput())



    class Meta:

        model = Document

        fields = ("field1", "field2", "form_lines")

So essentially, I need to get the per field definition of id or class, from the widget on the model, and combine that with the template defined form-control or is-valid/invalid classes in the template.

I've tried going down this route

How to concatenate strings in django templates?

But it just seems like it's going to end up in a huge mess.

Essentially, how can I combine template defined attributes and per field defined attributes? I need to end up with class="form-control field1-choice-ajax" for the field specified in the model (and the correct extra class names for the valid/invalid states).

Previously I was using the bootstrap4 form library, but I need complete control now:

{% csrf_token %}

{% bootstrap_form form %}

I've created my own template filter in order to add class attributes to existing form fields:

@register.filter

def add_class(field, css):

    """Add a class to a field in a template.



    Example:

        > {{ form.my_field|add_class:"required" }}

        <input id="my_field_id" name="my_field" class="required" type="text">



    Args:

        field: this should be a form field, of type ``BoundField``

        css: this should be a string with one or more class names separated by spaces

    """

    class_old = field.field.widget.attrs.get('class', None)

    class_new = class_old + ' ' + css if class_old else css

    return field.as_widget(attrs={'class': class_new})

So now I can do this in a template:

{{ field|add_class:"is-valid" }}