flask wtforms-alchemy QuerySelectField ValueError: too many values to unpack (expected 2)

Question

我正在尝试使用 flask-wtf 和 wtforms-alchemy 创建注册表单在这个表单上，我尝试创建 selectfield，它的值是从我的模型中查询的。但我总是得到这个错误：

 ValueError: too many values to unpack (expected 2)

这是我的代码:

from flask_wtf import FlaskForm
from wtforms_sqlalchemy.fields import QuerySelectField

def choose_domicile():
    return Domicile.query

class RegisterForm(FlaskForm):
    name = StringField('Name', validators=[DataRequired()])
    domicile = QuerySelectField(u'Domicile', query_factory=choose_domicile)


@app.route('/signup', methods=['GET', 'POST'])
    def signup():
        form = RegisterFormView()
        try:
            if form.validate_on_submit():
                new_user = Data(name=form.name.data, domicile=form.domicile.data)
                db.session.add(new_user)
                db.session.commit()
                return "Success"
        except:
            return "Failed"

        return render_template('signup.html', form=form)

这是我的signup.html:

{% block content %}
<div class="container">

  <form class="form-signin" method="POST" action="/signup">
    <h2 class="form-signin-heading">Sign Up</h2>
    {{ form.hidden_tag() }}
    {{ wtf.form_field(form.name) }}
    {{ form.domicile }}
    <button class="btn btn-lg btn-primary btn-block" type="submit">Sign Up</button>
  </form>

</div>
{% endblock %}

我的包版本是 flask-wtf==0.14.2 和 wtforms-alchemy==0.16.7

我已经尝试遵循这个 Why does Flask WTForms and WTForms-SQLAlchemy QuerySelectField produce too many values to unpack? ，但我仍然不知道该怎么做。

Answer 1

您可以定义一个函数，如下所示，它可以作为 get_pk 参数传递。

def get_pk(obj):
    return str(obj)

然后进行以下更改

domicile = QuerySelectField(u'Domicile', query_factory=choose_domicile, get_pk=get_pk)

我假设您已经在模型 class else return pk 中定义了 __str__ get_pk

flask wtforms-alchemy QuerySelectField ValueError: too many values to unpack (expected 2)

flask wtforms-alchemy QuerySelectField ValueError: too many values to unpack (expected 2)

python

sqlalchemy

flask

flask-sqlalchemy

flask-wtforms