When a client wishes to have exact control over how individually named properties of an object are saved, it would attempt to use an objectÆs IPersistPropertyBag interface as a persistence mechanism. In that case the client supplies a property bag to the object in the form of an IPropertyBag interface.

When the object wishes to read a property in IPersistPropertyBag::Load it will call IPropertyBag::Read. When the object is saving properties in IPersistPropertyBag::Save it will call IPropertyBag::Write. Each property is described with a name in pszPropName whose value is exchanged in a VARIANT. This information allows a client to save the property values as text, for instance, which is the primary reason why a client might choose to support IPersistPropertyBag.

The client records errors that occur during reading into the supplied error log.

Methods in Vtable Order

IUnknown Methods                       Description                                    
                                                                                      

QueryInterface                         

Returns pointers to supported interfaces.      
                                                                                      

AddRef                                 Increments reference count.                    
                                                                                      

Release                                Decrements reference count.                    
                                                                                      

IPropertyBag Methods                   Description                                    
                                                                                      

Read                                   

Asks the property bag to read the specified    
                                       property into a caller-initialized VARIANT.     
                                                                                      

Write                                  Asks the property bag to save the specified    
                                       property using the type and value in the        
                                       caller-initialized VARIANT.                     
                                                                                      

See Also

IErrorLog, IPersistPropertyBag