This class implements IUnknown and allows an object to save its properties to a client-supplied property bag.
Your class, derived from IPersistPropertyBagImpl.
The IPersistPropertyBag interface allows an object to save its properties to a client-supplied property bag. Class IPersistPropertyBagImpl provides a default implementation of this interface and implements IUnknown by sending information to the dump device in debug builds.
IPersistPropertyBag works in conjunction with IPropertyBag and IErrorLog. These latter two interfaces must be implemented by the client. Through IPropertyBag, the client saves and loads the object's individual properties. Through IErrorLog, both the object and the client can report any errors encountered.