I'm trying to concatenate a filtered column into a single cell separated with commas, only visible non empty cells.

Public Function Parts(myRange As Range)

    Dim aOutput As String, entry As Range

    For Each entry In myRange

        If entry.EntireColumn.Hidden = False Then

            aOutput = aOutput & entry.Value & ","

        End If

    Next

    Parts = Left(aOutput, Len(aOutput) - 1)

End Function