CODEWITHSUNDEEP
pythonwtformsflask-wtforms
heapOverflow
heapOverflow

Reputation: 1275

Is it possible to not have a default in QuerySelectField while not allowing blank in the validation?

I am generating a field with WTForms using a code similar to this:

my_field = QuerySelectField(
    'My Field',
    query_factory=lambda: MyClass.query
)

But in this case I got back all my elements of type MyClass and the first one is automatically selected.

If I change it in this way:

my_field = QuerySelectField(
    'My Field',
    query_factory=lambda: MyClass.query,
    allow_blank = True
)

The default selection is now empty, which is what I want, but the empty selection is now valid, when instead I want it to be an error.

Is there a way to not have a default but still being able to not make the selection optional?

Upvotes: 1

Views: 971

Answers (2)

Mithokai
Mithokai

Reputation: 3

You can create a custom validator to invalidate the default selection created by allow_blank = True.

Using InputRequired() or DataRequired() would not work because the default "blank" selection has a value of __None thus allowing the my_field validation to pass.

from wtforms.validators import ValidationError

class Form(FlaskForm):
    my_field = QuerySelectField(
        'My Field',
        query_factory=lambda: MyClass.query,
        allow_blank = True
    )

    @staticmethod
    def validate_my_field(self, field):
        if field.data is None:
            raise ValidationError("Please select a value.")

Upvotes: 0

Doobeh
Doobeh

Reputation: 9440

Adding a DataRequired validation to the form for that field would seem the easiest way.

from wtforms import validators

my_field = QuerySelectField(
    'My Field',
    query_factory=lambda: MyClass.query,
    allow_blank=True,
    validators=[validators.DataRequired()]
)

Upvotes: 2

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