How do you override the default value of a field in a dexterity behavior in Plone?

Question

We have a requirement for a dexterity content type to have exclude from navigation behaviour but for the exclude_from_nav field's default value to be True. In the behaviour plone.app.dexterity.behaviors.exclfromnav.IExcludeFromNavigation it defaults to False. Obviously I could create my own behaviour that copies IExcludeFromNavigation except for the default value but I was wondering if there was a way to do this based on reusing IExcludeFromNavigation. We have other content types that use IExcludeFromNavigation where we do want it to default to False. We're using Plone 4.1rc3 and Dexterity 1.0 JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

See http://plone.org/products/dexterity/documentation/manual/developer-manual/advanced/defaults and http://pypi.python.org/pypi/plone.directives.form#value-adapters, but basically: @form.default_value(field=IExcludeFromNavigation['exclude_from_nav'], context=IMyType) def excludeFromNavDefaultValue(data): return True Cheers, Martin