API Reference > imodeljs-backend > Relationships > Relationship > onRootChanged onRootChanged MethodStatic Callback invoked by saveChanges on an ElementDrivesElement relationship when its input has changed or is the output of some upstream relationship whose input has changed. This callback is invoked after the input element has been processed by upstream relationships. A subclass of ElementDrivesElement can re-implement this static method to take some action. onRootChanged may modify the output element only. onRootChanged(_props: RelationshipProps, _iModel: IModelDb): void Parameter Type Description _props RelationshipProps The ElementDrivesElement relationship instance. _iModel IModelDb The iModel Returns - void Defined in core/backend/src/Relationship.ts Line 51 Last Updated: 12 June, 2024