Using VB 2005 to detect whether a PDF is a collection

Question

I'm having a bear of a time using my rudimentary programming skills (Visual Basic 2005) to write a utility that will scan a folder containing PDF files and then list which of them contains a collection (either a Package or a Portfolio).
I've been able to create the file-side piece (allow the user to select the folder, scan the folder and populate a ListBox with all PDF files in the folder).
Now I have to scan those PDFs and determine whether or not any of them are PDF Collections (I then hope to populate another ListBox with that list of files). That's where I'm confused.
I've seen a number of examples of Programming Acrobat JavaScript using VB. I've also found one reference in the PDFTron Knowledge Base that discusses figuring out whether a PDF is a Collection. He uses the following to do that:
Obj collection = doc.GetRoot().FindObj("Collection");
if (collection != NULL) {
//This PDF contains a Collection
I can follow in general what this code fragment is doing but I can't seem to translate it into something useable in VB 2005.
I'm guessing that I need to somehow use GetJSObject (or maybe I'm wrong) but I can't figure out how or in what context I can get the collection information.
Additionally, I'm hoping that when my program runs through the list of PDFs looking for the collection info, I can do it without having Acrobat (or Reader) open. I don't know if this is possible (all of the samples that I've seen seem to initially open Acrobat).
Thanks, in advance, for your help!

Answer 1

Thanks Leonard!
Oh, I've been reading the documentation - my head is spinning from reading it for the past 2 days ! :-)
Unfortunbately, I've seen no sign of a doc.hasCollection() method.
I've found a "collection" property of the doc object in the Javascript for Acrobat API Reference.
I also found the "getDataObject" method for the doc object in the same document.
I became pretty excited when I found this one because if I click the link on that page to dataObjects, it tells me that it's an array containing all of the named data objects in a document.
If I click from there on the link to "data", it shoots me to the "data" page where I read:
"The following objects, properties and methods support PDF portfolios (also called PDF collections or PDF packages):
app.newCollection, Doc.collection, Collection object, and collectionField object".
Again, I think that I'm on the right track because it mentions the "Collection object" and "Doc.collection" but for the life of me, I can't figure out how to reference these properties in my program.
For instance:
       Dim varColl
        gPDDoc.Open("c:\adobe.pdf")
        jso = gPDDoc.GetJSObject
        varColl = jso.getdataobject.Collection()
tells me that I'm missing a required argument.
If I try something like:
       Dim varColl
        gPDDoc.Open("c:\adobe.pdf")
         jso = gPDDoc.GetJSObject
         varColl = jso.Collection()
Then I get:
"Public member 'Collection' on type '_ComObject' not found."
I'm sorry to be obtuse but I can't figure out how to reference these.
I've followed the examples in the "Programming Acrobat JavaScript Using Visual Basic" document and they all make sense. I just can't seem to get to the "Collection" information.
Any help would be greatly appreciated.
Thanks!