如何在敏捷的数据网格字段中为选择字段传递列表值？

Question

I have datagridfield in my Dexterity content type, using collective.z3cform. I have an interface classes, which defines the value_type as DictRow for the main datagridfield in my content type.

class IAssessment(interface):
    assessment_item=schema.Choice(
        title=u"Assessment Item",
        values=[u"Item 1",u"Item 2"],
        required=False
    )
    reference=schema.TextLine(title=u"Reference",required=False)


class Application(form.Schema,IImageScaleTraversable):
    form.widget(app_assessment=DataGridFieldFactory)
    app_assessment=schema.List(
        title=u"Application Assessment",
        value_type=DictRow(title=u"Application Assessment",schema=IAssessment)
    )

Is it possible to provide values for IAssessment under assessment_item field based on catalog query using portal_catalog from other content types. I got an errorr when I insert catalog=getToolByName(context, 'portal_catalog') since context is not defined, even if I put a parameter context in IAssessment, still I got the same error. Is there a way I can do catalog query in an interface class, if not are there any alternative ways?

Answer 1

You most likely want a context source binder, which is a form of dynamic vocabulary .

from zope.schema.interfaces import IContextSourceBinder
from zope.schema.vocabulary import SimpleVocabulary
from Products.CMFCore.utils import getToolByName

@grok.provider(IContextSourceBinder)
def assessmentItems(context):
    catalog = getToolByName(context, 'portal_catalog')
    return SimpleVocabulary.fromItems(
        (result.getId(), result.getObject()) for result in catalog(...)
    )

In your field definition, you then pass this in as vocabulary :

assessment_item=schema.Choice(
    title=u"Assessment Item",
    vocabulary=assessmentItems,
    required=False
)