Transport providers maintain two groups of properties known as message and recipient options. Message options are properties that affect the transmission of particular messages. Some of the message options can be used to alter the folder contents table display. For example, if each message in the folder has a setting for PR_IMPORTANCE or PR_SENSITIVITY, the settings can be handled differently. Messages with high importance might be bold while less important messages might appear in normal text. Messages that are extremely confidential might only appear after explicitly searching for them.
Some of the commonly supported message options include:
| Message option | Description |
|---|---|
| PR_SECURITY | To request additional security. Can be set to SECURITY_SIGNED or SECURITY_ENCRYPTED. |
| PR_PRIORITY | To establish a priority for delivery. Can be set to PRIO_URGENT, PRIO_NORMAL or PRIO_NONURGENT |
| PR_IMPORTANCE | To indicate a level of importance. |
| PR_SENSITIVITY | To indicate a level of privacy. |
| PR_DEFERRED_DELIVERY_ TIME |
To specify when a message should be delivered. |
| PR_EXPIRY_TIME | To specify a time limit for message delivery. |
| PR_LATEST_DELIVERY_TIME | To specify the latest time when a message can be delivered. |
Recipient options are properties that affect the processing of particular recipients. Recipient and message options affect a message after it has been submitted and usually correspond to a particular address type.
Default values for message and recipient options are established when MAPI calls a transport provider's IXPLogon::RegisterOptions method. Transport providers specify the properties in an array of property value structures included in the OPTIONDATA structure pointed to by the lppOptions parameter. Transport providers can register recipient options only, message options only, or both types of options.
You can retrieve the most current settings for the recipient option properties by calling either IAddrBook::RecipOptions or IAddrBook::QueryDefaultRecipOpt. RecipOptions displays a property sheet with the recipient option properties; QueryDefaultRecipOpt retrieves a property value array containing the settings.
Similar methods exist for retrieving the current message option properties. You can call IMAPISession::MessageOptions to allow users to view and change the settings and IMAPISession::QueryDefaultMessageOpt to retrieve the settings in a property value array.
Most transport providers supply a property sheet for displaying option properties. Some transport providers also allow users to make changes.