Getting incorrect attachment counts from IMESSAGE::GetAttachmentTable() API

Question

Hi All,

VC++, Visual Studio 2019

I am facing issues in accessing attachment counts, Here is the code flow:

LPMAPITABLE pATbl = NULL;
LPSRowSet pRow = NULL;

static SizedSPropTagArray(NUM_COLS, sptCols) = { NUM_COLS, PR_ENTRYID,
PR_MESSAGE_FLAGS,
PR_CREATION_TIME,
PR_SUBJECT };

enum { AttNum, AttType, AttFilename, NUM_ATT_COLS };
static SizedSPropTagArray(NUM_ATT_COLS, sptNum) = { NUM_ATT_COLS,
    PR_ATTACH_NUM,
    PR_ATTACH_METHOD,
    PR_ATTACH_LONG_FILENAME };

hr = pMessage->GetAttachmentTable(0, &pATbl);

hr = HrQueryAllRows(pATbl, (LPSPropTagArray)&sptNum,
NULL, NULL, 0, &pRow);

This above code is just to mentions the API used.

in case if my mail has 1 attachment, pRow->cRows value is 1.

when I try to access the attachment name it gives the correct attachment name. (success Scenario)

But in case if the mail has 1 attachment and it is digitally signed also, then also pRow->cRows value is 1. And when I try to access the attachment name it gives the incorrect attachment name(smime.p7m). (this smime.p7m is the attachment file name of the digital signature which gets added automatically)

Query: in case of digitally signed mail, why it is not showing 2 attachments? and How can I avoid this digital signature file programmatically.

Kindly guide or suggest me, I am stuck.

Thanks in advance.

Answer 1

It's a long time since I've done any MAPI, but I think you need to determine the message type via PR_MESSAGE_CLASS, and if it's a signed message, the smime.p7m attachment can be treated as a message itself, and it then has the underlying attachments.

OutlookSpy is an essential tool for examining and validating such inner workings.