Revit C# change Family Type

Question

I'm trying to change the family in the project. New family loads successfully but throws and exception Autodesk.Revit.Exceptions.InvalidOperationException: 'This Element cannot have type assigned.' when i try to ChangeTypeId of the old Family to new family GetTypeId();

    public void ReplaceTitleblock (Document cdoc)
    {
        string targetName = "TITLEBLOCK_AHMB";

        Family oldFamily = (from element in new FilteredElementCollector(cdoc).OfClass(typeof(Family))
                                           where element.Name == targetName && element.IsValidObject
                                           select element as Family).FirstOrDefault();

        Family newFamily;

        if (oldFamily != null)
        {
            cdoc.LoadFamily(newTitleblockPath, out newFamily);
            ElementId newElId = newFamily.GetTypeId();
            oldFamily.ChangeTypeId(newElId);
        }

any help on how to do this?

thanks, Luka

Answer 1

I got it to work.

I'm now iterating through FamilyInstances of the Family and replacing the FamilySymbol with new one

            foreach (FamilyInstance fam in oldFamilyInstancesFilter)
            {
                FamilySymbol newSymbol = cdoc.GetElement(newFamily.GetFamilySymbolIds().FirstOrDefault()) as FamilySymbol;
                fam.Symbol = newSymbol;
            }

i know there's only one symbol hence FirstOrDefault() method