SQL Alchemy / Flask / WTF表单为queryselectfield设置默认值

Question

I want to set a default value for my queryselectfield. My code looks like this:

Template:

{% import "bootstrap/utils.html" as utils %}
{% import "bootstrap/wtf.html" as wtf %}
{% extends "base.html" %}
{% block title %}Request{% endblock %}
{% block body %}
<div class="content-section">
...
{{ form.country(class_="selectformfield") }
...

Route:

@requests.route('/request/add', methods=['GET', 'POST'])
@login_required
def add_request():

check_admin()

add_request = True

form = RequestForm()
if form.validate_on_submit():
    ...
    Country = form.hostname.data
    ...

    request = Request(...country=country, ...)

    try:
        # add request to the database
        db.session.add(request)
        db.session.commit()
        flash('You have successfully added a new request.')
    except:
        # in case request name already exists
        flash('Error: request already exists.')

    # redirect to the request page
    return redirect(url_for('requests.show_request', id=request.id))

# load request template
return render_template('requests/add_request.html', add_request=add_request,
                       form=form, title='Add new Request')

Form:

class RequestForm(FlaskForm):
...
country = QuerySelectField(query_factory=lambda: Country.query.all(), get_label="name")
...

I already tried it like this, but it didn't work.

default_country = query_factory=lambda: Country.query.filter(Country.id == '1')
country = QuerySelectField(query_factory=lambda: Country.query.all(), get_label="name", default=default_country)

SQLAlchemy/WTForms: set default selected value for QuerySelectField I also already read this post here with a simmilar problem, but the solution doesn't work for me. Can annyone help me?

Answer 1

Try this:

default=lambda: Country.query.filter(Country.id == '1').one_or_none())

here the complete code of your field definition:

country = QuerySelectField(query_factory=lambda: Country.query.all(), get_label="name", default=lambda: Country.query.filter(Country.id == '1').one_or_none())