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Persisting the Expanded Node State
Updated on Jan 20, 2026
The DropDownTree enables you to define and persist the expanded state of its nodes when the popup TreeView is re-rendered.
Manual Setup
The DropDownTree exposes the following options to control the expanded state of its nodes:
isNodeExpanded((node: any) => boolean)—Determines if a given node is expanded.nodeCollapse(EventEmitter<any>)—Fired when a given node is about to be collapsed.nodeExpand(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.
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Using the Built-In Directive
By default, the built-in kendoDropDownTreeExpandable directive persists the expanded nodes based on their hierarchical index.
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