Determine if Outlook downloaded only the header of a message

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Applies to: Outlook 2013 | Outlook 2016

This topic shows a code sample in Visual C++ that uses the named PidLidHeaderItem Canonical Property to determine whether Microsoft Outlook 2013 has downloaded only the header of a message or the header and the body of a message.

BOOL bIsHeader(LPMESSAGE lpMessage) 
{ 
    HRESULT         hRes = S_OK; 
    BOOL            bRet = false; 
    ULONG    ulVal = 0; 
    LPSPropValue    lpPropVal = NULL; 
    LPSPropTagArray lpNamedPropTag = NULL; 
    MAPINAMEID      NamedID = {0}; 
    LPMAPINAMEID    lpNamedID = NULL; 
 
    NamedID.lpguid = (LPGUID) &PSETID_Common; 
    NamedID.ulKind = MNID_ID; 
    NamedID.Kind.lID = dispidHeaderItem; 
    lpNamedID = &NamedID; 
    hRes = lpMessage->GetIDsFromNames(1, &lpNamedID, NULL, &lpNamedPropTag); 
 
    if (lpNamedPropTag && 1 == lpNamedPropTag->cValues) 
    { 
lpNamedPropTag->aulPropTag[0] = CHANGE_PROP_TYPE(lpNamedPropTag->aulPropTag[0], PT_LONG); 
 
//Get the value of the property. 
hRes = lpMessage->GetProps(lpNamedPropTag, 0, &ulVal, &lpPropVal); 
if (lpPropVal && 1 == ulVal && PT_LONG == PROP_TYPE(lpPropVal->ulPropTag) && lpPropVal->Value.ul) 
{ 
    bRet = true; 
} 
    } 
 
    MAPIFreeBuffer(lpPropVal); 
    MAPIFreeBuffer(lpNamedPropTag); 
    return bRet; 
}