How to get QuerySelectField current value with Flask WTF

问题

If using SelectField we can get the current value that prepopulate in form from database using the obj argument, like this answer on my previous question.

For now, I want to get the current value using QuerySelectField.

Here is the snippet of my code:

def course_list():
    return Course.query.all()

class PaymentForm(Form):
    total_price = IntegerField(validators=[required()])
    course_name = QuerySelectField('Course name', validators=[required()], query_factory=course_list)
    # ....
    # ....

And here is the route.

@app.route('/edit_payment/<int:payment_id>', methods=['GET', 'POST'])
def edit_payment(payment_id):
    payment = Pament.query.filter_by(id=payment_id).first()
    course = db.session.query(Course.name).filter_by(id=payment.course_id).first()
    payment_form = PaymentForm(obj=course) # here I try to use the obj argument.
    # ... validate on submit
        # ....
        # ....
    return render_template(payment=payment, payment_form=payment_form)

On the route above which I call the PaymentForm, I try to parse the obj argument, but seems it did not prepopulate the value on current user from db.

here is how I call it on Jinja2 template:

{{ f.render_field(payment_form.course_name, value=payment.name) }}

So, the point of my question is, how to get the QuerySelectField value base on current user value on database..?

EDIT:

Here is the snippet of my model:

class Payment(db.Model):
    __tablename__ = 'payment'
    id = db.Column(db.Integer, primary_key=True)
    course = db.relationship('Course', backref=db.backref('payment', lazy='dynamic'))
    # ...
    # ...
    def __init__(self, course):
        self.course = course

class Course(db.Model):
    __tablename__ = 'course'
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String(100), unique=True)
    # ...
    # ...
    def __init__(self, name):
        self.name = name

And I also tried to pass the value on obj like this:

payment = Pament.query.filter_by(id=payment_id).first()
payment_form = PaymentForm(obj=payment)

回答1:

I figure out this by following this great answer.

来源：https://stackoverflow.com/questions/57863668/how-to-get-queryselectfield-current-value-with-flask-wtf

标签

python

Flask

jinja2

flask-wtforms

wtforms