Add fields dynamically to WTForms form

Question

I want to define a form class with fields based on a dict of name: label. I tried the following, which nearly worked. However, rendering the fields in a template gave AttributeError: 'UnboundField' object has no attribute '__call__'. How can I dynamically add fields to a form?

def build_form(name, record): class ContactForm(FlaskForm): name = StringField(name) fieldlist = {} for key, value in record.items(): fieldlist[key] = StringField(key) @app.route('/', methods=['GET', 'POST']) def showform(): form = ContactForm(request.form) if request.method == 'POST': return 'form processed' return render_template('cardcompare.tpl', record=record, form=form)

<form method=post> {{ form.name() }} {% for key, value in record.items() %} {{ form.fieldlist[key]() }} {% endfor %} <input type=submit value=Register> </form>

Feodoran · Accepted Answer · 2017-05-09 15:59:40Z

13

Use setattr to add new fields as attributes of the form class. This will cause WTForms to set up the field correctly instead of keeping the unbound field.

# form class with static fields class MyForm(FlaskForm): name = StringField('static field') record = {'field1': 'label1', 'field2': 'label2'} # add dynamic fields for key, value in record.items(): setattr(MyForm, key, StringField(value))

In the template you can iterate over the fields using the attr filter.

{% for key, value in record.items() %}: {{ form|attr(key)() }} {% endfor %}

edited May 9, 2017 at 15:59

answered May 9, 2017 at 15:16

Feodoran

1,8221 gold badge18 silver badges31 bronze badges

Sign up to request clarification or add additional context in comments.

10 Comments

Omniver Over a year ago

Thanks, is there a way though to get the dynamic fields added to a structure which can be iterated through in the template? (e.g. like fieldlist in the example)? The goal is to handle the dynamic fields differently than the static in the template.

Feodoran Over a year ago

That part was deleted a litte overeagerly by an edit. I recoverd it.

TomSawyer Over a year ago

I've done the same by putting setattr inside __init__ of MyForm , because i need to pass attribute list to the form, it works except the first time running, do you know why?

Feodoran Over a year ago

You need to add these fields to the class, not the instance. This means, before calling MyForm().

TomSawyer Over a year ago

@Feodoran i already added to the class but it only work since second form submit. Please take a look at my question here: stackoverflow.com/questions/2583620/…

|

Collectives™ on Stack Overflow

Add fields dynamically to WTForms form

1 Answer 1

10 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

10 Comments

Linked

Related