BodyPart Fields and Streams

The Microsoft Collaboration Data Objects (CDO) for Microsoft® Windows® 2000 messaging interface designs define common mechanisms for working with Multipurpose Internet Mail Extensions (MIME) and RFC 822 message headers that are consistent with other non-messaging interfaces and the Microsoft® ActiveX® Data Objects (ADO). Each interface defines an ADO Fields collection and defines access to the body parts associated content stream through an ADO Stream object. The diagram below, listing an attached Hypertext Markup Language (HTML) page, shows the relationship of the Fields collection and the various streams associated with a body part:

BodyPart Fields and Streams

The Fields collection consists of ADO Field objects. Each object contains a name and value pair that defines some aspect of the body part or message. The names of these properties (which are also referred to as fields) are a combination of Uniform Resource Identifiers (URIs) namespaces and a name. This convention is used to guarantee to a very high degree of certainty that each property is rendered globally unique within the scope of a namespace.

Each body part that is not multipart has an associated content stream. The stream can be requested in either decoded or encoded format. This stream contains the raw material of the body part; for example, a body part with content type application/msword has a content stream containing a binary word file (.doc). When returned decoded, the stream contains the file `as if it were on the file system as a series of bits. If the encoded stream is requested, the binary information is encoded using the mechanism specified by the urn:schemas:mailheader:content-transfer-encoding for the body part.