MAPI Properties

Description: Contains binary attachment data typically accessed through the Object Linking and Embedding (OLE) IStream interface.
Property ID: $3701
Property type: PT_BINARY
Area: Message attachment

This property holds the attachment when the value of the PR_ATTACH_METHOD (PidTagAttachMethod) property is ATTACH_BY_VALUE, which is the usual attachment method and the only one required to be supported. PR_ATTACH_DATA_BIN also holds an OLE 1.0 OLESTREAM attachment when the value of PR_ATTACH_METHOD is ATTACH_OLE.
OLESTREAM attachments can be copied into a file by calling the OLE IStream::CopyTo method. The OLE encoding type can be determined from the PR_ATTACH_TAG (PidTagAttachTag) property.
For an OLE document file attachment, the message store provider must respond to an IMAPIProp::OpenProperty call on PR_ATTACH_DATA_OBJ (PidTagAttachDataObject) and may optionally respond to a call on PR_ATTACH_DATA_BIN. Note that PR_ATTACH_DATA_BIN and PR_ATTACH_DATA_OBJ share the same property identifier and thus are two renditions of the same property.
For a storage object, such as a compound file in OLE 2.0 docfile format, some service providers allow it to be opened with the MAPI IStreamDocfile interface for improved performance. A provider that supports IStreamDocfile must expose it on PR_ATTACH_DATA_OBJ and may optionally expose it on PR_ATTACH_DATA_BIN.