How does Outlook create Task Requests?

Question

I have been working with EWS Managed API and have frequently come across posts for Assign Task or Task Requst creation is not supported by EWS.

http://social.msdn.microsoft.com/Forums/exchange/en-US/53418cb8-9fb8-4f4d-9bcf-d314909e9eb9/create-task-request-using-ews?forum=exchangesvrdevelopment

http://social.msdn.microsoft.com/Forums/exchange/en-US/82574974-890b-4c13-849f-73f111906b98/send-a-task-request-using-ews?forum=exchangesvrdevelopment

But we can create Task Requests from Outlook. How does Outlook do that? What API does it use in the back to achieve this?

Is there a way to use the same API that Outlook uses to achieve this functionality?

Answer 1

Outlook internally uses Extended MAPI (accessible in C++ or Delphi only).

You can use the Outlook Object Model or Redemption (I am its author), which wraps Extended MAPI.

If you need to build a task request without using the MAPI system in one form or another, you would need to build a winmail.dat attachment, which is a TNEF stream containing MAPI specific properties used by task requests.