Error while getting pointer of a sub folder

[Nauman Hameed]

Hi

I am trying to open the Inbox folder of an Exchange Server mailbox. I
follow these steps to do this.

1. Initialize MAPI (MAPIInitialize)
2. Create a session using an explicit profile (MAPILogonEx)
3. Get the message stores table (session->GetMsgStoresTable)
4. Open the required message store after getting the entry ID from the
table obtained in step 4 (session->OpenMsgStore)
5. Get the root folder entry ID from the message store (msgStore->GetProps
to get PR_IPM_SUBTREE_ENTRYID property)
6. Open the root folder using the entry ID obtained in step 5.
(msgStore->OpenEntry)
7. Get the hierarchy table for the root folder
(rootFolder->GetHierarchyTable)
8. Get the entry ID of a sub folder, e.g. Inbox, from the hierarchy table (
the PR_LONGTERM_ENTRYID_FROM_TABLE property )
9. Open the sub folder using the entry ID obtained in step 8
(rootFolder->OpenEntry)

The code works fine upto step 9. The code for step 9 returns successfully (
hr == S_OK ). However, when I try to use the pointer of sub folder for any
operations on the sub folder, I get an exception with the message "Object
reference not set to an instance of an object."

I have used the GetReceiveFolder method as well (msgStore-

GetReceiveFolder). The results are same. The entry ID that I get in step 8
and the entry ID that I get using the GetReceiveFolder are same.

I have verified the entry ID that I get in my code using OutlookSpy.
OutlookSpy reports the same entry ID for the Inbox folder. If I use the
OpenEntry dialog provided by OutlookSpy, it successfully opens the Inbox
folder using the same entry ID.

I use following lines of code to open the sub folder (Inbox folder).

/---------------------------\
SBinary subFolderEID;
LPMAPIFOLDER subFolder = NULL;

ULONG lpulObjType;
LPUNKNOWN lppUnk = NULL;

hr = rootFolder->OpenEntry(subFolderEID.cb, (LPENTRYID) subFolderEID.lpb,
&IID_IMAPIFolder, MAPI_MODIFY, &lpulObjType, &lppUnk);

subFolder = (LPMAPIFOLDER) &lppUnk;
\----------------------------/

In the OpenEntry call I have tried different combinations of flags other
than MAPI_MODIFY but no use.

Can anyone provide some insight?

Thanks
Nauman

[Nauman Hameed]

Found the solution from another forum. The last line of the code pasted below
is:

subFolder = (LPMAPIFOLDER) &lppUnk;

The & with lppUnk is the culprit. It should be:

subFolder = (LPMAPIFOLDER) lppUnk; // Without the &

Nauman

"Nauman Hameed" wrote:

Hi

I am trying to open the Inbox folder of an Exchange Server mailbox. I
follow these steps to do this.

1. Initialize MAPI (MAPIInitialize)
2. Create a session using an explicit profile (MAPILogonEx)
3. Get the message stores table (session->GetMsgStoresTable)
4. Open the required message store after getting the entry ID from the
table obtained in step 4 (session->OpenMsgStore)
5. Get the root folder entry ID from the message store (msgStore->GetProps
to get PR_IPM_SUBTREE_ENTRYID property)
6. Open the root folder using the entry ID obtained in step 5.
(msgStore->OpenEntry)
7. Get the hierarchy table for the root folder
(rootFolder->GetHierarchyTable)
8. Get the entry ID of a sub folder, e.g. Inbox, from the hierarchy table (
the PR_LONGTERM_ENTRYID_FROM_TABLE property )
9. Open the sub folder using the entry ID obtained in step 8
(rootFolder->OpenEntry)

The code works fine upto step 9. The code for step 9 returns successfully (
hr == S_OK ). However, when I try to use the pointer of sub folder for any
operations on the sub folder, I get an exception with the message "Object
reference not set to an instance of an object."

I have used the GetReceiveFolder method as well (msgStore-
GetReceiveFolder). The results are same. The entry ID that I get in step 8
and the entry ID that I get using the GetReceiveFolder are same.

I have verified the entry ID that I get in my code using OutlookSpy.
OutlookSpy reports the same entry ID for the Inbox folder. If I use the
OpenEntry dialog provided by OutlookSpy, it successfully opens the Inbox
folder using the same entry ID.

I use following lines of code to open the sub folder (Inbox folder).

/---------------------------\
SBinary subFolderEID;
LPMAPIFOLDER subFolder = NULL;

ULONG lpulObjType;
LPUNKNOWN lppUnk = NULL;

hr = rootFolder->OpenEntry(subFolderEID.cb, (LPENTRYID) subFolderEID.lpb,
&IID_IMAPIFolder, MAPI_MODIFY, &lpulObjType, &lppUnk);

subFolder = (LPMAPIFOLDER) &lppUnk;
\----------------------------/

In the OpenEntry call I have tried different combinations of flags other
than MAPI_MODIFY but no use.

Can anyone provide some insight?

Thanks
Nauman