There are no numeric values or constants used to call GetProperty().
When you call GetProperty() you use a DASL-style property tag string, for example to get the mail Internet headers (PR_TRANSPIORT_MESSAGE_HEADERS) you would use the following property tag string (not a URL): "http://schemas.microsoft.com/mapi/proptag/0x007D001F"
Open the Outlook VBA project (Alt+F11 in Outlook) and use the Object Browser to look at the Help for PropertyAccessor and methods such as GetProperty() and SetProperty() to see how such accesses are done.
To get the DASL property tags the easiest way is to use a MAPI viewer such as OutlookSpy(www.dimastr.com/outspy). Select an item, click the IMessage button and look at the DASL field
when you select a property in the GetProps tab. When using folder properties use the IMAPIFolder button, for Store properties use the IMsgStore button.
Where can I find documentation on the numeric values or constants used to call the PropertyAccessor.GetProperty methods on different Outlook objects?
mdpowers
Ken Slovak MVP - Outlook