InternalDefinition.BuiltInParameter always INVALID

[cig_ad]

Why is this the case? The collected ParameterElements definitely include builtin definitions.

            var defs = new FilteredElementCollector(commandData.Application.ActiveUIDocument.Document)
                           .OfClass(typeof(ParameterElement)).OfType<ParameterElement>()
                           .Select(p => p.GetDefinition())
                           .Where(d => d.BuiltInParameter != BuiltInParameter.INVALID)
                           .ToList();

Tested in Revit 2019 + 2020

Thanks, Peter

[cig_ad]

Ok - never mind. I guess a ParameterElement is defined as 'An Element that stores a user-defined parameter.' - so by definition not builtin. It seems that there are some unexpected parameters floating around in the document that I mistook for builtins...