The MessagePart property returns the current message part
index. All messages have at least one part, which consists of one
or more header fields, followed by the body of the message. The
default part, part 0, refers to the main message header and body.
If the message contains multiple parts (as with a message that
contains one or more attached files), the MessagePart
property can be set to refer to that specific part of the
message.
Messages with file attachments typically consist of a message
part which describes the contents of the attachment, followed by
the attachment itself. For a message with one attached file, there
would be a total of three parts. Part 0 would refer to the main
message part, which contains the headers such as From, To, Subject,
Date and so on. For multipart messages, part 0 typically does not
have a message body, since any text is usually created as a
separate part (for those messages that do not contain multiple
parts, the part 0 body contains the text message). Part 1 would
contain the text describing the attachment, and part 2 would
contain the attachment itself. If the attached file is binary, then
the transfer encoding type would usually be base64.