将自定义对象传递给 WTForm

Question

我需要将一个对象从我的数据库传递到我的表单，我想从中读取默认值。我当前的代码如下所示：

我的初始化：

form = EditEventForm(event)

还有我的表格 class:

class EditEventForm(FlaskForm):
    def __init__(self, event):
        self.event = event

    name = StringField('Name', validators=[DataRequired()],     default=self.event.name)
    description = TextAreaField('Description', validators=[DataRequired()], default=self.event.description)
    street = StringField('Street and number', validators=[DataRequired()], default=self.event.street)
    city = StringField('City', validators=[DataRequired()], default=self.event.city)
    time = StringField('Time', validators=[DataRequired()], default=self.event.time)

但显然，表单无法访问自身上下文。有没有其他方法可以实现它，以便我的字段可以从传递的对象中读取数据？

Answer 1

如果您的任务只是用默认数据填充表单，您可以这样做：

from flask_wtf import Form
from wtforms import StringField, TextAreaField
from wtforms.validators import DataRequired

class EditEventForm(Form):
    name = StringField('Name', validators=[DataRequired()])
    description = TextAreaField('Description', validators=[DataRequired()])
    street = StringField('Street and number', validators=[DataRequired()])
    city = StringField('City', validators=[DataRequired()])
    time = StringField('Time', validators=[DataRequired()])

然后用所需数据填充新创建的表单

form = EditEventForm()
form.name.data = event.name
form.description.data = event.description
form.street.data = event.street
form.city.data = event.city
form.time.data = event.time

编辑

正如评论中所建议的那样，上述模式是错误的，因为当模型或表单对象发生更改时，必须跟踪所有表单创建实例。可以改用这样的东西：

# attributes of the event object matching form field names will be used for field values
form = EditEventForm(obj=event)

# populates the attributes of the passed obj with data from the form’s fields
form.populate_obj(event)

来自documentation：

Note: This is a destructive operation; Any attribute with the same name as a field will be overridden. Use with caution.

Answer 2

来自the FineManual：

init(formdata=None, obj=None, prefix='', data=None, meta=None, **kwargs) Parameters:
(...) obj – If formdata is empty or not provided, this object is checked for attributes matching form field names, which will be used for field values.

将自定义对象传递给 WTForm

Pass custom object to WTForm

python

flask

python-3.x

wtforms

flask-wtforms