INFO: Save Message to MSG Compound File

This article was previously published under Q171907
This article contains code that demonstrates how to save a message to acompound document--specifically an .msg file--that is readable by anyclient that supports the .msg file format.
The function below takes a valid message object as an in parameter and usesits properties to create a duplicate of the message and save it to acompound file using the .msg format. The subject line of the message isused as the file name of the new file.

NOTE: Special characters in the subject line of the in parameter of thisfunction can cause unexpected results. While code can be written to avoidspecial characters in the subject line, it is not germane to the topic andsuch code is intentionally left out.
#define INITGUID#include <objbase.h>#define USES_IID_IMessage#include <mapix.h>#include <mapitags.h>#include <mapidefs.h>#include <mapiutil.h>#include <mapiguid.h>#include <imessage.h>// {00020D0B-0000-0000-C000-000000000046}DEFINE_GUID(CLSID_MailMessage,0x00020D0B,0x0000, 0x0000, 0xC0, 0x00, 0x0, 0x00, 0x0, 0x00, 0x00, 0x46);HRESULT SaveToMSG ( LPMESSAGE pMessage ){    HRESULT hRes = S_OK;    LPSPropValue pSubject = NULL;    LPSTORAGE pStorage = NULL;    LPMSGSESS pMsgSession =  NULL;    LPMESSAGE pIMsg = NULL;    SizedSPropTagArray ( 7, excludeTags );    char szPath[_MAX_PATH];    char strAttachmentFile[_MAX_PATH];    LPWSTR lpWideCharStr = NULL;    ULONG cbStrSize = 0L;    // create the file name in the directory where "TMP" is defined    // with subject as the filename and ".msg" extension.    // get temp file directory    GetTempPath(_MAX_PATH, szPath);    // get subject line of message to copy. This will be used as the    // new file name.    HrGetOneProp( pMessage, PR_SUBJECT, &pSubject );    // fuse path, subject, and suffix into one string    strcpy ( strAttachmentFile, szPath );    strcat ( strAttachmentFile, pSubject->Value.lpszA  );    strcat ( strAttachmentFile, ".msg");    // get memory allocation function    LPMALLOC pMalloc = MAPIGetDefaultMalloc();    // Convert new file name to WideChar    cbStrSize = MultiByteToWideChar (CP_ACP,                                     MB_PRECOMPOSED,                                     strAttachmentFile,                                     -1, lpWideCharStr, 0);    MAPIAllocateBuffer ( cbStrSize * sizeof(WCHAR),                            (LPVOID *)&lpWideCharStr );    MultiByteToWideChar (CP_ACP,                         MB_PRECOMPOSED,                         strAttachmentFile,                         -1, lpWideCharStr, cbStrSize );    // create compound file    hRes = ::StgCreateDocfile(lpWideCharStr,                              STGM_READWRITE |                              STGM_TRANSACTED |                              STGM_CREATE, 0, &pStorage);    // Open an IMessage session.    hRes = ::OpenIMsgSession(pMalloc, 0, &pMsgSession);    // Open an IMessage interface on an IStorage object    hRes = ::OpenIMsgOnIStg(pMsgSession,                            MAPIAllocateBuffer,                            MAPIAllocateMore,                            MAPIFreeBuffer,                            pMalloc,                            NULL,                            pStorage,                            NULL, 0, 0, &pIMsg);    // write the CLSID to the IStorage instance - pStorage. This will    // only work with clients that support this compound document type    // as the storage medium. If the client does not support    // CLSID_MailMessage as the compound document, you will have to use    // the CLSID that it does support.    hRes = WriteClassStg(pStorage, CLSID_MailMessage );    // Specify properties to exclude in the copy operation. These are    // the properties that Exchange excludes to save bits and time.    // Should not be necessary to exclude these, but speeds the process    // when a lot of messages are being copied.    excludeTags.cValues = 7;    excludeTags.aulPropTag[0] = PR_ACCESS;    excludeTags.aulPropTag[1] = PR_BODY;    excludeTags.aulPropTag[2] = PR_RTF_SYNC_BODY_COUNT;    excludeTags.aulPropTag[3] = PR_RTF_SYNC_BODY_CRC;    excludeTags.aulPropTag[4] = PR_RTF_SYNC_BODY_TAG;    excludeTags.aulPropTag[5] = PR_RTF_SYNC_PREFIX_COUNT;    excludeTags.aulPropTag[6] = PR_RTF_SYNC_TRAILING_COUNT;    // copy message properties to IMessage object opened on top of    // IStorage.    hRes = pMessage->CopyTo(0, NULL,                            (LPSPropTagArray)&excludeTags,                            NULL, NULL,                            (LPIID)&IID_IMessage,                            pIMsg, 0, NULL );    // save changes to IMessage object.    pIMsg -> SaveChanges ( KEEP_OPEN_READWRITE );    // save changes in storage of new doc file    hRes = pStorage -> Commit(STGC_DEFAULT);    // free objects and clean up memory    MAPIFreeBuffer ( lpWideCharStr );    pStorage->Release();    pIMsg->Release();    CloseIMsgSession ( pMsgSession );    pStorage = NULL;    pIMsg = NULL;    pMsgSession = NULL;    lpWideCharStr = NULL;    return hRes;}				
All versions of Outlook and the Exchange Client support CLSID_MailMessage as the compound document. The only reason to use a different CLSID is to support other clients that use a different CLISD when you write messages to structured storage.

When saving messages which have a large number of recipients or attachments, it is possible that the CopyTo operation will fail with MAPI_E_NOT_ENOUGH_MEMORY. This is due to a known problem with structured storage and streams. Every time that a new attachment or recipient is added to the message being saved in structured storage, a new Root Storage File is opened. These files are not closed until the transaction is completed. Because the operating system imposes a limit on the number of simultaneously open root storage files, there is no known workaround. For additional information, click the article number below to view the article in the Microsoft Knowledge Base:
163202 Limit of the Number of Simultaeously Open Root Storage Files
All versions of Outlook are affected by this limitation as well.

Αναγνωριστικό άρθρου: 171907 - Τελευταία αναθεώρηση: 08/18/2005 18:00:56 - Αναθεώρηση: 2.5

Microsoft Office Outlook 2007, Microsoft Messaging Application Programming Interface, Microsoft Exchange Client 5.5, Microsoft Exchange Client 5.0, Microsoft Exchange Client 4.0, Microsoft Exchange Client 5.0

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