Because the Microsoft Exchange Server information store is a MAPI information store, the fields on LitCrit forms exist as MAPI properties. You can use CDO calls to read and write MAPI properties. A message can contain two kinds of MAPI properties, standard and user-defined.
Standard MAPI properties are the common message properties such as Subject, To, From, Conversation, or message class. The following line of code stores the value of message class, using the MAPI property tag to identify it:
MessageClass = msgTarget.Fields(MAPI_PROPTAG_MESSAGECLASS).Value
User-defined properties (also known as named properties) are MAPI properties for which you create your own MAPI property tags. For more information, see the Properties section in the Messaging API (MAPI) section of the Platform SDK.
User-defined MAPI properties are created specifically for the application, such as the following ones used for LitCrit: isApproved, ApprovalRequired, CritiqueNo. The following line of code stores the value of the ApprovalRequired property, using the name assigned to it by the F & M developers.
ApprovalRequired = msgTarget.Fields("ApprovalRequired").Value