Automatic Property Promotion

[This is preliminary documentation and subject to change.]

The Web Store automatically sets properties for messaging items when the associated stream is written to the Web Store. You control this behavior through the file name extension of the item. When you create an item with an .eml extension, and write the item's stream, the Web Store assumes that the stream is formatted according to the RFC 822 and MIME standards. It examines the inbound stream for various messaging-related values, such as mail header fields and message text, and automatically sets these properties for the item. This is referred to as property promotion; the promotion is from data within the stream to properties for the item. The Web Store checks the stream for all properties defined by the urn:content-classes:message content class for promotion.

In the following code example, you create an item in your inbox with the name "mymessage.eml", you also save and commit the following stream to the item in the Web Store:

To: "User 1" <User1@microsoft.com>
From: "User 2" <user2@microsoft.com>
Subject: This is the subject.

This is the text of the message.

The following table lists the properties for the items after saving the stream.

The Web Store automatically set the value for these properties (promoted the properties) using the values present within the written stream.

Note   The Web Store does not automatically update the stream for the message when the properties are changed using OLE DB or Active Data Object (ADO) directly. You must update the stream separately. To avoid updating the stream separately, use the CDO Message or CalendarMessage objects when modifying existing items in the Web Store. These objects automatically ensure that messaging properties and the item stream remain synchronized.