python - 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)

还有我的表单类:

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.