ITnef : IUnknown
Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here. ArchiveDisclaimer

ITnef : IUnknown

This content is outdated and is no longer being maintained. It is provided as a courtesy for individuals who are still using these technologies. This page may contain URLs that were valid when originally published, but now link to sites or pages that no longer exist.

Provides methods for encapsulating MAPI properties that are not supported by a messaging system into binary streams that can be attached to messages. The format used for this encapsulation is the Transport-Neutral Encapsulation Format (TNEF). The target transport provider or MAPI-based client application can then, on receiving a message that includes a TNEF attachment, recover the properties from the attachment.

Header file:


Exposed by:

TNEF objects

Implemented by:


Called by:

Transport providers, message store providers, and gateways

Interface identifier:


Pointer type:



Enables the calling service provider or gateway to add properties to the encapsulation of a message or an attachment.


Extracts the properties from a TNEF encapsulation.


Finishes processing for all TNEF operations that are queued and waiting.


Opens a stream interface on the text of an encapsulated message.


Sets the value of one or more properties for an encapsulated message or attachment without modifying the original message or attachment.


Encodes a view for a message's recipient table in the TNEF data stream for the message.


Processes individual components from a message one at a time into a TNEF stream.

© 2016 Microsoft