Revit 2020 Window Function Type Parameter

[Sean_Page]

I have an application that loops nearly every model element in an attempt to set it to the correct Workset, but it is breaking in Revit 2020 when running against elements in the Window category. The error is when I try to retrieve the "Function" (BuiltInParameter.FUNCTION_PARAM) and it is returning a NullReferenceException. When I get into the model it appears that "Function" no longer a Type Parameter.

Would someone verify this parameter is in fact gone?

[jeremytammik · Accepted solution]

How about simply checking for null before dereferencing the parameter?

[Sean_Page]

Yes, that would be  a perfect solution, especially had I actually read my code well enough to notice that I was checking the Function of the HOSTWALL and not the actual Window. My issue is NOT with the Window... apparently its with my Eyes!

[Sean_Page · Accepted solution]

Just so I circle back on this and close it up, here is what I ended up with, which was checking for the Null Host using an "is" statement once I realized it was a random Modeled In Place family of "Window" category throwing the exception.

foreach (Element window in Helpers.Collectors.ByCategoryNotElementType(doc, BuiltInCategory.OST_Windows))
                        {
                            method = "Windows";
                            if (!window.get_Parameter(BuiltInParameter.ELEM_PARTITION_PARAM).IsReadOnly)
                            {
                                elems++;
                                if (doc.GetElement(window.get_Parameter(BuiltInParameter.HOST_ID_PARAM).AsElementId()) is Wall hostWall)
                                {
                                    if (Helpers.Parameters.Tbip(doc, hostWall, BuiltInParameter.FUNCTION_PARAM).AsInteger() == 0)
                                    {
                                        window.get_Parameter(BuiltInParameter.ELEM_PARTITION_PARAM).Set(Helpers.Worksets.WorksetIdByName(doc, "A-INTERIOR").IntegerValue);
                                    }
                                    else
                                    {
                                        window.get_Parameter(BuiltInParameter.ELEM_PARTITION_PARAM).Set(Helpers.Worksets.WorksetIdByName(doc, "A-EXTERIOR").IntegerValue);
                                    }
                                }
                            }
                        }