Persisting the Expanded Node State
The DropDownTree enables you to define and persist the expanded state of its nodes when the popup TreeView is re-rendered.
The DropDownTree exposes the following options to control the expanded state of its nodes:
(node: any) => boolean)—Determines if a given node is expanded.
EventEmitter<any>)—Fired when a given node is about to be collapsed.
EventEmitter<any>)—Fired when a given node is about to be expanded.
The following example demonstrates how to manually track and control the expanded node state.
Using the Built-In Directive
By default, the built-in
kendoDropDownTreeExpandable directive persists the expanded nodes based on their hierarchical index.