xaf-nonpersistent

To create non-persistent objects in XAF, decorate classes with the [DomainComponent] attribute and inherit from NonPersistentBaseObject. You must also register them using the AddNonPersistent() method in the application builder to generate UI for non-persistent objects.

A SessionMixingException occurs when non-persistent objects inherit from XPO persistent base classes. To fix this, ensure your non-persistent objects do not inherit from persistent base classes and use the [DomainComponent] attribute instead of the [NonPersistent] attribute.

In XAF, the [DomainComponent] attribute enables non-persistent objects with full UI generation, while the [NonPersistent] attribute from XPO has a different meaning and should not be used for this purpose. Using the wrong attribute prevents the framework from managing your temporary data correctly.

To populate a NonPersistentObjectSpace with external data, handle the ObjectsGetting event to populate lists and the ObjectByKeyGetting event to populate single items. This approach allows you to load computed views or external data dynamically into XAF List and Detail views.

Yes, you can use PopupWindowShowAction dialogs to build temporary input forms in XAF. By combining these dialogs with non-persistent objects managed by a NonPersistentObjectSpace, you can capture user input without storing the underlying data in a database table.

Use non-persistent objects in XAF when dealing with data loaded from external sources, computed at runtime, or used as temporary input forms. They generate full UI including List Views, Detail Views, and Actions without mapping to any database table, ideal for dynamic read-only or transient data.