wtforms-alchemy-如何用关系数据预填充表单？

Question

so...

This:

model_dictionary = model.as_dict() # some kind of dictionary
form = TheModelsForm(**model_dictionary) # https://wtforms-alchemy.readthedocs.io/en/latest/advanced.html
form.populate_obj(model)
return form

This let's me pre populate the model's form with fields from the model that are db.Columns.. Well.. what about db.relationships on the model?

The above code is not pre-populating the relationship fields; they show up but are left blank. Only the db.Column fields are pre-populated with values regardless of whether I force include the relationship values in the model_dictonary or not (for example, model_dictionary['key_from_other_object'] = associated value).

Can this be accomplished? --Can't find anything on this..

Edit: I solved my initial problem with:

form = TheModelsForm(obj=model)
form.populate_obj(model)
return form

Now I'm trying to figure out how to get the events on the location's model to actually show up on the Location form...

class Event(Base):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String())
    location_id = db.Column(db.Integer, db.ForeignKey('location.id'))

class Location(Base):
    id = db.Column(db.Integer, primary_key=True)
    name = db.Column(db.String())
    events = db.relationship('Event', backref=db.backref('events'))

I'm sure there is a logical reason why all the stuff I commented out isn't working.. I'm getting 'NoneType' object is not iterable

class EventForm(ModelForm):
    class Meta:
        model = models.Event

    location_id = fields.SelectField(u'Location', coerce=int)


 class LocationForm(ModelForm):
        class Meta:
            model = models.Location

        #events = fields.SelectField(u'Event', choices=[(g.id, g.selector) for g in models.Event.query.all()], coerce=int)

        # events = fields.SelectMultipleField('Event', 
        #     choices=[(g.id, g.selector) for g in models.Event.query.all()],
        #     coerce=int,
        #     option_widget=widgets.CheckboxInput(),
        #     widget=widgets.ListWidget(prefix_label=False)
        #     )

        #events = ModelFieldList(fields.FormField(EventForm))

Answer 1

was barking up the wrong tree using SelectMultipleField and SelectField..

Instead,

wtforms_alchemy.fields.QuerySelectMultipleField @ https://media.readthedocs.org/pdf/wtforms-alchemy/latest/wtforms-alchemy.pdf

and

this post, which helped to show usage, @ WTForms QuerySelectMultipleField Not sending List

solved my problem..

..ended up with

class LocationForm(ModelForm):
    class Meta:
        model = models.Location

    events = wtforms_alchemy.fields.QuerySelectMultipleField('Event', 
        query_factory=lambda: models.Event.query.order_by(models.Event.name).all(), 
        get_label= lambda x: x.name,
        option_widget=widgets.CheckboxInput(),
        widget=widgets.ListWidget(prefix_label=False)
        )