Flask-当数据库文件被分离时，如何在wtf表单中填充select字段？

我已经分离模型文件和使用应用程序工厂。项目结构如下： 像这样：

project/
|-- config.py
|-- core.py      # app factory definition which calls db.init_app(app)
|-- database.py  # models definition and 'db = SQLAlchemy()' is done here
|-- forms.py     # forms definition.
|-- __init__.py  # app = create_app() is done here
\-- routes.py

class ArticleForm(Form):
    title = StringField()
    content = TextAreaField()
    category = SelectField(
        choices=[(c.id, c.name) for c in Category.query.all()]
    )

我有两个模型：文章和类别。然后，在

forms.py

中，我尝试 像这样：

project/
|-- config.py
|-- core.py      # app factory definition which calls db.init_app(app)
|-- database.py  # models definition and 'db = SQLAlchemy()' is done here
|-- forms.py     # forms definition.
|-- __init__.py  # app = create_app() is done here
\-- routes.py

class ArticleForm(Form):
    title = StringField()
    content = TextAreaField()
    category = SelectField(
        choices=[(c.id, c.name) for c in Category.query.all()]
    )

因此，

Category.query.all（）

在应用程序上下文外部调用，并引发以下问题：

RuntimeError: application not registered on db instance and no application
bound to current context

那么，如何使用数据库中的现有数据填充

选择字段？
您可以使用WTForms的扩展：

from flask_wtf import Form
from wtforms.fields import StringField, TextAreaField
from wtforms.ext.sqlalchemy.fields import QuerySelectField
from database import Category

class ArticleForm(Form):
    title = StringField()
    content = TextAreaField()
    category = QuerySelectField(query_factory=lambda: Category.query.all())

这篇博文帮助了我，因为我无法得到我想要的工作的公认答案。也可以删除导入


我使用了他的第二种技巧，对于这个问题

from flask_wtf import Form
from wtforms.fields import StringField, TextAreaField
from database import Category

class ArticleForm(Form):
    title = StringField()
    content = TextAreaField()
    category = SelectField()

    def __init__(self):
        super(ArticleForm, self).__init__()
        self.category.choices = [(c.id, c.name) for c in Category.query.all()]

这个语法对我不起作用，所以我不得不调整它为：def uuu init_uuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuuu