WTForms SelectField 返回 None

Question

I'm using WTForms and Flask, I am trying to create a form where I can enter information about a recipe, but the product_name SelectField is returning None every time.

The form:

class CreateRecipeForm(Form):
    product_name = SelectField(choices=get_craftables_options())
    product_quantity = IntegerField(default=1)
    job_field = SelectField(choices=['ALC', 'GSM', 'WVR'])
    line_item_list = FieldList(FormField(RecipeLineForm), min_entries=6)
    save_button = SubmitField()

The view:

@bp.route('/edit/new', methods=('GET', 'POST'))
def create_recipe():
    form = CreateRecipeForm()
    if request.method == 'POST':
        selected_product = Item.query.get(form.product_name.data)
        (do stuff here)

The template

{% block content %}
    <form method="post">
        {{ render_field(form.product_name) }}
        {{ render_field(form.product_quantity) }}
        {{ render_field_no_label(form.line_item_list) }}
        {{ render_field_no_label(form.save_button) }}
    </form>
{% endblock %}

Answer 1

I believe your issue lies in declaring the product_name. Make sure the get_craftables_options() is supposed to be a function and is returning a list of items compatible with the choices argument.

product_name = SelectField(choices=get_craftables_options())