如何使用 WTForms-Alchemy 添加文本字段占位符

Question

I'm currently using WTForms-Alchemy for creating forms for my database models.

My User.py looks like this:

class User(UserMixin, db.Model, CreationDateMixin):
   __tablename__ = 'user'

   id = db.Column(db.Integer, primary_key=True)
   first_name = db.Column(db.String(50), info={
      'label': 'Firstname',
      'validators': validators.Length(min=3)
   })

For the Model I defined a form using WTForms-alchemy:

class EditProfileForm(ModelForm, FlaskForm):
   class Meta:
      model = User

   submit = SubmitField("Update")

And I'm using the form in a Jinja2 Template file like this:

{{ form.short_name }}

Is there a way to define a placeholder for the text input in the User.py class? I already tried adding a the parameter 'placeholder' to the info block but this didn't work.

Answer 1

WTForms has an argument render_kw which is a dict describing arguments to pass to the render widget for the form object. [ https://wtforms.readthedocs.io/en/stable/fields.html#the-field-base-class ]

The info argument is a dict of arguments to pass to the WTForms functions so the solution is to pass a dict of another dict:

class User(UserMixin, db.Model, CreationDateMixin):
   __tablename__ = 'user'

   id = db.Column(db.Integer, primary_key=True)
   first_name = db.Column(db.String(50), info={
      'label': 'Firstname',
      'validators': validators.Length(min=3),
      'render_kw': {'placeholder': 'FIRST NAME'}
   })