API Reference > ui-components > Tree > TreeEventHandler TreeEventHandler Class Default tree event handler. Implements TreeEvents IDisposable Methods Name Description constructor(params: TreeEventHandlerParams): TreeEventHandler dispose(): void Disposes tree event handler. onCheckboxStateChanged(__namedParameters: TreeCheckboxStateChangeEventArgs): undefined | Subscription Changes nodes checkbox states. onDelayedNodeClick(__namedParameters: TreeNodeEventArgs): void Activates node editing if editing parameters are supplied and node is editable. onNodeCollapsed(__namedParameters: TreeNodeEventArgs): void Collapses node onNodeEditorActivated(__namedParameters: TreeNodeEventArgs): void Activates node editing if editing parameters are supplied and node is editable. onNodeExpanded(__namedParameters: TreeNodeEventArgs): void Expands node and starts loading children. onSelectionModified(__namedParameters: TreeSelectionModificationEventArgs): undefined | Subscription Selects and deselects nodes until event is handled, handler is disposed or selection replaced event occurs. onSelectionReplaced(__namedParameters: TreeSelectionReplacementEventArgs): undefined | Subscription Replaces currently selected nodes until event is handled, handler is disposed or another selection replaced event occurs. Properties Name Type Description modelSource Accessor ReadOnly TreeModelSource Defined in ui/components/src/ui-components/tree/controlled/TreeEventHandler.ts Line 49 Last Updated: 11 June, 2024