SQLAlchemy/WTForms: set default selected value for QuerySelectField

问题

This [example][1] to set up a form with WTForms and SQLAlchemy in Flask and add a QuerySelectField to the form works. I am not using flask.ext.sqlalchemy, my code:

ContentForm = model_form(Content, base_class=Form)
ContentForm.author = QuerySelectField('Author', get_label="name")
myform = ContentForm(request.form, content)
myform.author.query = query_get_all(Authors)

Now I want to set the default value of the QuerySelectField's selectlist.

Tried passing a default kwarg in QuerySelectField and setting selected attributes. Nothing worked. Am I missing something obvious? Can someone help?

回答1:

You need to set your default keyword argument to the instance of Authors that you want to be the default:

# Hypothetically, let's say that the current user makes the most sense
# This is just an example, for the sake of the thing
user = Authors.get(current_user.id)
ContentForm.author = QuerySelectField('Author', get_label='name', default=user)

Alternately, you can provide the instance to the field on instantiation:

# The author keyword will only be checked if
# author is not in request.form or content
myform = ContentForm(request.form, obj=content, author=user)

回答2:

Try this:

ContentForm.author = QuerySelectField(
    'Author', 
    get_label="name", 
    default=lambda: Authors.get(current_user.id).one()
)

来源：https://stackoverflow.com/questions/21579373/sqlalchemy-wtforms-set-default-selected-value-for-queryselectfield