IBaseMessageContext Interface (COM)

 

Provides access to the properties of the message and allows promotion of the properties.

For a list of all members of this type, see IBaseMessageContext Members.

Note

For information on using this interface within managed code, see the IBaseMessageContext Interface.

Remarks

This interface encapsulates the message context, which is essentially a property bag for storing object properties. The context object is contained within the message.

Notice that existing properties never have a NULL value. A NULL value means that the property does not exist. For example:

• Attempting to set (or promote) a property value to NULL deletes the property with S_OK.

• Attempting to read a nonexistent property returns NULL with S_OK.

• For predicate-related interfaces, "x:a=NULL" (VT_NULL), which is the same as the hypothetical NotExists(x:a) predicate, is the test for nonexistence of a property x:a.

Multivalued property values are still contained in the same single variant value (pVar).

See Also

IBaseMessageContext Members (COM)