Fail to Loop Through Items in a SelectionSet

I am trying to use VBA to loop through all the items in a selection-set
to find their patterns. Unfortunately, I keep getting the following
error message when I use Item() method of the selection-set to try to
get acess to an item in the selection-set:
Error Number: -2147418113
Error Description: Method 'Item' of object 'IAcadSelectionSet'
failed

How should I get around with this problem? Is there an alternative?

The following is a sample program that shows the error:

Private Sub SavePcInfoToArray()
'Save the info of all the pieces into an array.

Dim objSelectSet As AcadSelectionSet
Dim anFilterTypes(3) As Integer
Dim avFilterValues(3) As Variant
Dim nCur As Integer
Dim objItem(100) As Object

m_nTotalGrpPcInfo = 0

On Error GoTo Err_SavePcInfoToArray

Set objSelectSet = ThisDrawing.SelectionSets.Add("AllPcs")

anFilterTypes(0) = -4: avFilterValues(0) = "<or"
anFilterTypes(1) = 8: avFilterValues(1) = "My_Flex"
anFilterTypes(2) = 8: avFilterValues(2) = "My_Rect"
anFilterTypes(3) = -4: avFilterValues(3) = "or>"
objSelectSet.Select acSelectionSetAll, , , _
anFilterTypes, avFilterValues

'Here, the program shows the correct number of
'items selected. So far so good.
ThisDrawing.Utility.Prompt vbCrLf & _
"Total Pieces Selected: " & objSelectSet.Count

'Trying to loop through each item in the
'selection set. But failed at Item() method.
For nCur = 0 To objSelectSet.Count - 1
Set objItem(nCur) = objSelectSet.Item(nCur)
Next nCur

objSelectSet.Delete
Exit Sub

Err_SavePcInfoToArray:
If (Not objSelectSet Is Nothing) Then
objSelectSet.Delete
End If
MsgBox "Error # " & Err.Number & ": " & Err.Description
Exit Sub
End Sub

Thanks in advance for any help.

Jay Chan

 

I change the loop to something like this, but it still doesn't work:

Dim objItem As AcadEntity

 

Turns out this problem has something to do with the fact that those
items are drawn using CAD-Duct (a third party software running on top
of AutoCAD). The properties of the items that are drawn using CAD-Duct
is in a different format than regular generic items that are drawn
using pure AutoCAD. That explains the reason why I cannot use Item()
method to get access to the properties of the items drawn using
CAD-Duct.

Based on some past posts in a different forum, I am supposed to be able
to get around with this problem by installing something called Object
Enabler that I can download from CAD-Duct web site. Unfortunately,
that Object Enabler trick doesn't work in AutoCAD 2007 that I am
currently using. In other words, this is yet another deadend.

The bottom line is that I cannot use VBA to get access to properties of
items drawn by CAD-Duct as long as I am using AutoCAD 2007. I will
have to use the combination of VisualLISP and a Scripting API that
CAD-Duct has offered as an option (for additional $$$).

Jay Chan