How to find Calendar ID - vba

Question

I need to find the ID of a Outlook Calendar. It is a public calendar with many contributors/users, but not listed as "shared".
I want to automatically export selected calendars to an *.ics.
Currently I only can export my default folder with:
Set oNamespace = Application.GetNamespace("MAPI")
Set oFolder = oNamespace.GetDefaultFolder(olFolderCalendar)
Set oCalendarSharing = oFolder.GetCalendarExporter
oCalendarSharing.SaveAsICal "C:\calendar.ics"
I need to add the "ThisOne" to the export.
The properties do not have a location:
How to I find the ID, so I can use it with "GetFolderFromID()"? Or are there better ways to include the Calendar in the export or export it on its own?
Edit:
Now I think I got the Calendar-ID by using
Set oNamespace = Application.GetNamespace("MAPI")
Set oFolderPicked = oNamespace.PickFolder
Set oFolder = oNamespace.GetFolderFromID(oFolderPicked.EntryID, oFolderPicked.StoreID)
Set oCalendarSharing = oFolder.GetCalendarExporter
but this throws a exception at the last line (GetCalendarExporter):
If I export in the GUI (File -> Save), it works without a problem...
(Later I dont want to use PickFolder and just hard-code the EntryID to the script)

Answer 1

Open Outlook -> Goto Calendar of choice -> Alt F11 -> Immediate Window -> Type the following and hit enter.
? ActiveExplorer.CurrentFolder.EntryID

Answer 2

This demonstrates how to get the EntryID of a folder.
Option Explicit
Sub entryIDFromActiveExplorer()
Dim entryIDStr As String
Dim uPrompt As String
Dim uTitle As String
Dim uDefault As String
Dim msg As String
' Select a folder in the folder view
' Do not use the calendar view
entryIDStr = ActiveExplorer.CurrentFolder.entryID
uPrompt = "To hardcode the entryID of the " & _
Session.GetFolderFromID(entryIDStr) & _
" folder, copy this ID"
' Copy from the immediate pane
Debug.Print uPrompt
Debug.Print entryIDStr
uTitle = Session.GetFolderFromID(entryIDStr)
uDefault = entryIDStr
msg = InputBox(Prompt:=uPrompt, Title:=uTitle, Default:=uDefault)
End Sub
Sub entryIDFromPickfolder()
' If you do not want to select a folder
' in the normal way, from the GUI
Dim oFolderPicked As folder
Dim entryIDStr As String
Dim uPrompt As String
Dim uTitle As String
Dim uDefault As String
Dim msg As String
Set oFolderPicked = Session.PickFolder
If Not oFolderPicked Is Nothing Then
entryIDStr = oFolderPicked.entryID
uPrompt = "To hardcode the entryID of the " & _
Session.GetFolderFromID(entryIDStr) & _
" folder, copy this ID"
' Copy from the immediate pane
Debug.Print uPrompt
Debug.Print entryIDStr
Set ActiveExplorer.CurrentFolder = Session.GetFolderFromID(entryIDStr)
DoEvents
uTitle = Session.GetFolderFromID(entryIDStr)
uDefault = entryIDStr
msg = InputBox(Prompt:=uPrompt, Title:=uTitle, Default:=uDefault)
End If
ExitRoutine:
Set oFolderPicked = Nothing
End Sub