Exchange Server: Enhancing support for Custom Item Classes

The Exchange Team is considering for future Microsoft Exchange Server 2007 service packs and future releases of Exchange Server to enhance support for item classes for which EWS doesn’t have a corresponding type, as one area where we can improve your experience with EWS. This proposed modification will change some of the default behavior, and before we make […]

The Exchange Team is considering for future Microsoft Exchange Server 2007 service packs and future releases of Exchange Server to enhance support for item classes for which EWS doesn’t have a corresponding type, as one area where we can improve your experience with EWS. This proposed modification will change some of the default behavior, and before we make our final decision, we’d like to get your feedback.  If you are aware of any potential problems or existing coding patterns that would break as a result of this design change, please leave your comments below. 
 
When EWS returns an item that has an ItemClass that doesn’t map to a strong type, it returns that item as an ItemType.  For example, a developer could choose to store an item with a custom item class (i.e. “Item.Custom”) in Exchange. Because EWS doesn’t have a strong type for “Item.Custom”, the item would be returned as an ItemType.  These items create problems for EWS developers because ItemType objects cannot be sent by using the SendItem method. These items cannot be sent because they lack a number of key properties – i.e. ToRecipients, CcRecipients, Sender, and so on. Another issue developers have when working with these items is that there is no way to mark them as Read/Unread. The potential solution we’ve come up with is to have EWS return these items as messages.

Full Article