Creat view filter for project parameter

[SeanP]

Take a look at this link, I think it will solve what you are looking for. The reason it that a “List” in python is not completely equivalent to an ICollection in the Revit API.

How to create an icollection to work with revit api

You have done it in line 38. Try to replace ids with col1 in line 44 Edit: To answer the title of the thread: A C# ICollection(ElementId) equivalent in python : List[ElementId] Remember the following reference clr.AddReference(“System”) from System.Collections.Generic import List Example: col1 = List[ElementId](ids)