MAPI defines several groups of properties that describe a messaging user or distribution list. Each group is built around five properties known as the base address properties. When a messaging user or distribution list is included as a recipient in a message, these properties are copied to the message. The base address properties are:
PR_ADDRTYPE
PR_DISPLAY_NAME
PR_EMAIL_ADDRESS
PR_ENTRYID
PR_SEARCH_KEY
Base address properties are maintained for every address book entry and for many message recipients. Not all of the address property groups contain all five properties. Particular properties may not be defined for these groups because the likelihood of their being needed or used is not great. However, if a client or provider discovers a need for them, or for any other property undefined by MAPI, they can create their own user-defined properties. For more information about creating custom properties, see Defining New Properties.
MAPI provides these groups of address properties to save clients and service providers time and work. Included in these groups are properties that are frequently accessed. Having them within a message saves clients and service providers from having to call OpenEntry to open the address book object and either GetProps or OpenProperty to access the properties. These address book calls are expensive in code size and execution time.
The property tags for the other groups of address properties use PR_ as the standard prefix and the rest of the base property tag as a suffix, inserting a character string in the middle to further describe the recipient and the context in which the property is being used. For example, PR_SENDER_ENTRYID is the property tag for the entry identifier of the sender of a message and PR_SENT_REPRESENTING_ENTRYID is the property tag for the entry identifier of a delegate sender.
The following table lists the different groups of address properties built on the base address properties that exist in MAPI.
| Address property group | Description |
|---|---|
| Base address properties | Describe a messaging user or distribution list. |
| PR_SENT_REPRESENTING_ properties |
Describe the delegate sender of a message. |
| PR_RECEIVED_BY_ properties | Describe the recipient of a message. |
| PR_SENDER_ properties | Describe the sender of a message. |
| PR_RCVD_REPRESENTING_ properties |
Describe the delegate recipient of a message. |
| PR_ORIGINAL_AUTHOR_ properties | Describe the author of the first version of a message. |
| PR_ORIGINAL_SENT_REPRESENTING_ properties | Describe the delegate sender of the first version of a message. |
| PR_ORIGINALLY_INTENDED_RECIP_ properties | Describe the recipient for whom an autoforwarded message was originally intended. |
| PR_ORIGINAL_SENDER_ properties | Describe the sender of the first version of a message. |
| PR_REPORT_ properties | Describe the recipient of a report message. |