What timestamp, when the item was received or sent? For received time use
the ReceivedTime property of the item, for the time it was sent use the
SentOn property.
To retrieve the last action taken on an email item you must use a lower
level API such as Redemption (
www.dimastr.com/redemption) or CDO 1.21 (not
supported for managed code and subject to the Outlook security) or Extended
MAPI (unmanaged C++ or Delphi only), or some other MAPI wrapper such a
MAPI33.
Only the last action taken is available, there is no history of actions, so
a forward followed by a reply will only show the reply.
The property to look at in that case is PR_LAST_VERB_EXECUTED (property tag
0x10810003), which can be one of 3 PT_LONG (32-bit int) values:
EXCHIVERB_REPLYTOSENDER == 102
EXCHIVERB_REPLYTOALL == 103
EXCHIVERB_FORWARD == 104