GetElement() returning null on selected ElementId within Family Document

[Anonymous]

Hello,

I'm having an issue, where I select an element, retrieve its ID, however when I try doc.GetElement() it returns null. I'm wondering if it is because I am running this in a family document (something I am not used to)

Document doc = this.Document;
if( !doc.IsFamilyDocument )
{
     TaskDialog.Show("Fam Doc", "Must be run in a family document");
}
			
FamilyManager mgr = doc.FamilyManager;
			
Selection selection = this.Application.ActiveUIDocument.Selection;
ICollection<ElementId> selectedIds = selection.GetElementIds();
ElementId id = selectedIds.First();
            
// is null
Element test = doc.GetElement(id);
// fails because test is null
ParameterSet pSet = test.Parameters;

Attached is the family file I am using, I selected element 3008 (the upper middle extrusion on the Ref. Level floor plan), however any element selection should yield the same failure. 

Thanks!

[jeremytammik]

In the code snippet you show above, there is no guarantee that 

  Document doc = this.Document;

is the same as

  this.Application.ActiveUIDocument

I suggest that you eliminate the latter and use one single `doc` variable to address both.

You are using the former document and an element id from the latter.

This will certainly fail if the two differ.

Cheers,

Jeremy

[Anonymous · Accepted solution]

Jeremy's answer is correct I believe, just wanted to add what fixed it for me was in macro manager creating for "application" rather than the specific project. Good luck!