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PidTagMessageFlags Canonical Property
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Contains a bitmask of flags that indicate the origin and current state of a message.
This property is a nontransmittable message property exposed at both the sending and receiving ends of a transmission, with different values depending upon the client application or store provider involved. This property is initialized by the client or message store provider when a message is created and saved for the first time and then updated periodically by the message store provider, a transport provider, and the MAPI spooler as the message is processed and its state changes.
This property exists on a message both before and after submission, and on all copies of the received message. Although it is not a recipient property, it is exposed differently to each recipient according to whether it has been read or modified by that recipient.
One or more of the following flags can be set for this property:
A client or message store provider can check the current state of the message at any time by calling the IMAPIProp::GetProps method to read the flag values. The client or provider can also call the IMAPIProp::SetProps method to change any flags that currently have read/write access.
Several of the flags are always read-only. Some are read/write until the first call to the IMAPIProp::SaveChanges method and thereafter become read-only as far as IMAPIProp::SetProps is concerned. One of these, MSGFLAG_READ, can be changed later through IMessage::SetReadFlag or IMAPIFolder::SetReadFlags.
The initial values for this property are typically MSGFLAG_UNSENT and MSGFLAG_UNMODIFIED to indicate a message that has not yet been sent or changed. When a message is saved for the second time, the message store provider clears the MSGFLAG_UNMODIFIED flag. Another value that a message store provider can set when a message is saved is the MSGFLAG_HASATTACH flag, indicating that the message has one or more attachments. The PR_HASATTACH property is computed from this setting.
When a client calls the IMessage::SubmitMessage method to send the message, the message store provider makes a copy of it for the MAPI spooler and updates this property by setting the MSGFLAG_SUBMIT flag. The message store provider also sets MSGFLAG_UNSENT if it is not yet set. MSGFLAG_SUBMIT indicates that SubmitMessage has been called, beginning the send process, and that the message is now read-only to the client. MSGFLAG_UNSENT indicates that the MAPI spooler is handling the message. If the send process is canceled, the message store provider resets this flag.
When the message is given to a transport provider for delivery, the transport provider sets the MSGFLAG_FROMME flag if the sender had the same account on the messaging server as the message was received on. Transport providers set MSGFLAG_FROMME for an incoming message that was sent by the currently logged on user. A client can use this value to determine that it is more appropriate to show recipient names in the contents table of the Sent Items folder than sender names. Messages that have been saved during the composition process and not yet sent should also be displayed with recipient names rather than sender names.
For an incoming message, a message store provider clears the MSGFLAG_READ flag to reset its read status. A client can set or clear the MSGFLAG_READ flag when it is necessary to change the read status and control the sending of read and nonread reports, by calling either the message's IMessage::SetReadFlag method or its folder's IMAPIFolder::SetReadFlags method. The main difference between these methods, other than the object implementing them, is that the folder method can affect one, several, or all of the messages in the folder. The message method affects a single message.
A client should also test an incoming message for the MSGFLAG_ORIGIN_X400, MSGFLAG_ORIGIN_INTERNET, and MSGFLAG_ORIGIN_MISC_EXT flags. These flags are set by the inbound transport provider and indicate that the message arrived from a source that the gateway cannot consider trusted. This means the message originated either outside the organization, or internally but from a workstation not known to the gateway. In any case, the identity of the sender may not be confirmed, and there is a risk of introducing a computer virus into the organization. The client should display a warning message to the user and offer an option of deleting the message without opening it.
Message store providers set the MSGFLAG_UNMODIFIED flag for incoming messages. MSGFLAG_UNMODIFIED indicates that a message has not been changed since delivery. A client cannot clear this value after it has been set by a message store provider.