The IMAPIMessageSite::SubmitMessage method requests that the current message be submitted to the MAPI spooler.
See IMAPIMessageSite : IUnknown.
HRESULT SubmitMessage(
ULONG ulFlags
);
Form objects call the IMAPIMessageSite::SubmitMessage method to request that a message be submitted to the MAPI spooler. The message site should call the IPersistMessage::HandsOffMessage method prior to submitting the message. The message need not have previously been saved, as SubmitMessage should cause the message to be saved if it has been modified. Following the return of SubmitMessage, the form must check for a current message and then dismiss itself if none exists.
For a list of interfaces related to form servers, see MAPI Form Interfaces.
IPersistMessage::HandsOffMessage