Accessing contacts in outlook / exchange through VSTO

I'm writing a Outlook add-in that needs to access Outlook contacts. 开发者_运维知识库I have successfully obtained a list of local contacts but cant seem to find an example that will give me access to the list of shared contacts using VSTO.

Application
  .GetNamespace("MAPI")
  .AddressLists["Global Address List"]
  .AddressEntries