extends Field

[This is preliminary documentation and subject to change.]

Used when defining a content class to indicate the list of content classes this class extends.

Full Name

urn:schemas-microsoft-com:xml-data#extends

OLE DB Type

DBTYPE_VECTORE | DBTYPE_WSTR

Remarks

This multi-valued string property lists the names of content classes a class extends. The class definition thereby inherits the properties defined by those content classes. Additional properties defined for a content class are listed in the urn:schemas-microsoft-com:xml-data#element property. A content class can extend any number of content classes, including none.

A content class definition can simply extend another class and not list additional property definition names. In this case, the content class is equivalent to the extended content class, differing only in name. In other words, the list of references property definitions is the same for both classes.

For example, you may wish to define a set of custom content classes for each specific type of document in an application you create. When you define these content classes, you can have each class "inherit" the properties defined by the base urn:content-classes:document content class. In this way, you avoid having to list all of numerous properties already defined by this base content class in the definition item's urn:schemas-microsoft-com:xml-data#element property. Depending upon your intended use for these custom content classes, you may add your own additional custom property definition references to these classes as well.