WtfFroms Pre poulate ListField

Question

What i want to populate the data to list field before rendering the tamplete. This is what i have so far.

class SizeVariationForm(Form):
    name = TextField("name")
    sku = TextField("SKU Number")


class AddVariationForm(NewListingForm):
    item_list = FieldList(FormField(SizeVariationForm))
    add_field = SubmitField('Add Variations')


@app.route('/index', methods=['GET', 'POST'])
def add_inputs():
    form = AddVariationForm(request.form)
    if form.add_field.data:
        # what i want is to poluate sku data here

        new_variation = form.item_list.append_entry()
        return render_template('index')

The current result is

<input id="item_list-0-variation"  value="">

Desired result is

<input id="item_list-0-variation" value="Some Value here">

Answer 1

You will get expected output but I am not sure this is what you want.

class SizeVariationForm(Form):
    name = TextField("Name")
    sku = TextField("SKU")

class TestForm(Form):
    item_list = FieldList(FormField(SizeVariationForm))
    add_field = SubmitField("Add Variations")

@app.route('/index', methods=['GET', 'POST'])
def add_inputs():
    f = SizeVariationForm()
    form = AddVariationForm()
    if request.method == 'POST':
        f.name.data = "Same value"
        f.sku.data = "sku data"
        form.item_list.append_entry(f)
    return render_template('index.html', form=form)

#index.html
<form method="POST", action="/">
        {{form.item_list}}
        {{form.add_field.label}}{{form.add_field}}
</form>

Answer 2

The base class Field accepts a default argument.

default – The default value to assign to the field, if no form or object input is provided. May be a callable.

Provide this argument to the field's init method. IE

class MyForm(Form):
    foo = SomeField("Bar", default="Example")

http://wtforms.simplecodes.com/docs/0.6.1/fields.html