Navisworks API selection null reference exception

[rade_tomovic]

I asked the same question on stack overflow, without answers, so I will link it here. Basically, I'm getting null reference exception on this code:

_doc.CurrentSelection.CopyFrom(selection);

but neither _doc, CurrentSelection or selection are null or empty. 

[niels_deboer]

selection is a List<ModelItem> object type and not ModelItemCollection. It is not the same, see below. If you change the GroupIntersectingClashResults object type to this it could solve your problem.

C#

public class ModelItemCollection : NativeHandle, 
	ICollection<ModelItem>, IEnumerable<ModelItem>, IEnumerable