BCGControlBar Pro for MFC
BOOL CBCGPAppointmentPropertyList::Add ( DWORD  ID,
CBCGPAppointmentBaseProperty pProperty 

Adds a property to the "property bag".

TRUE, if the property with specified ID does not exist in the "property bag" and the property has been added successfully; otherwise FALSE.

Use this method to add a new property with the specified by ID identifier to the property list. If a property with such ID has been added, the function returns FALSE.

You should use CBCGPAppointmentPropertyList::Set method to change the property data located at the specified ID.

IDSpecifies the ID at which the property should be added.
pPropertyPoints to a property to add.