PRB: Cannot Store PR_ENTRYID in a Fixed Length Field

• Extended Messaging Application Programming Interface (MAPI), version 1.0

SYMPTOMS

When you encounter this problem, you have difficulty storing the PR_ENTRYID property into a fixed length field.

CAUSE

The size of an EntryID is implementation specific and not defined. Therefore, defining a fixed length field for storing a variable size EntryID, in a database for example, would be impossible.

RESOLUTION

You can use the PR_SOURCE_KEY property to calculate the PR_ENTRYID on a message or folder. Because PR_SOURCE_KEY is always a 22-byte property on Exchange Server, you can define the size of a field in the database in order to store this property. The PR_SOURCE_KEY can then be used to calculate the PR_ENTRYID through the use of the EntryIDFromSourceKey API.

For a message, you will also need the PR_SOURCE_KEY of the containing folder to calculate the message's PR_ENTRYID.

Sample Code

//Get the SourceKey on the newly created Message
hr = HrGetOneProp(lpMessage, PR_SOURCE_KEY, &lpMessageSK);

//Get the SourceKey on the message's containing folder
hr = HrGetOneProp(lpMessageCont, PR_SOURCE_KEY, &lpMessageFoldSK);

//Get the EntryID from the PR_SOURCE_KEYs that we just 
//retrieved.
ULONG                   ulSizeOfEntryIDSK       = 0;
LPENTRYID               lpEntryIDSK             = 0;
LPEXCHANGEMANAGESTORE   lpXManageStore          = 0;
ULONG                   lpulEntryIDResults      = 0;

//Get a pointer to the IExchangeManageStore Interface off the store,
//through QueryInterface.
hr = lpDefStore->QueryInterface(IID_IExchangeManageStore,
                                (LPVOID*)&lpXManageStore);

//Run EntryIDFromSourceKey to get the message or folders EntryID
hr = lpXManageStore->EntryIDFromSourceKey(lpMessageFoldSK->Value.bin.cb,
                                          lpMessageFoldSK->Value.bin.lpb,
                                          lpMessageSK->Value.bin.cb,
                                          lpMessageSK->Value.bin.lpb,
                                          &ulSizeOfEntryIDSK,
                                          &lpEntryIDSK);
 

STATUS

This behavior is by design.

MORE INFORMATION

The PR_SOURCE_KEY property is not valid for messages and folders in Exchange Personal Message Stores(.PST).

The IExchangeManageStore(IID_IExchangeManageStore) GUID can be found in the EDKGUID.h header file.

REFERENCES

For more information on PR_SOURCE_KEY property and the EntryIDFromSourceKey API, please refer to the Microsoft Developer Network.

Additional query words: MAPI PR_SOURCE_KEY PR_ENTRYID EntryID EntryIDFromSourceKey kbDSupport kbGrpMsg kbMsg kbVC600 kbMAPI

Keywords          : kbMAPI kbMsg kbVC600 kbGrpMsg kbDSupport 
Version           : WINDOWS:1.0
Platform          : WINDOWS 
Issue type        : kbprb 

Last Reviewed: June 10, 1999