TreeView Expanded Items

Updated on Oct 1, 2026

TreeView lets the user expand multiple items. It also gives the option to pre-expand a specific item.

To use the item expansion, set the ExpandedItems parameter. It allows two-way binding (@bind-ExpandedItems) and one-way binding + ExpandedItemsChanged event.

The ExpandedItems collection is of type IEnumerable<object>.

Programmatically Expand and Collapse Items

Programmatically expand and collapse items on button click.

Example

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See Also

• TreeView Overview
• TreeView Data Binding
• TreeView Events
• Expand and collapse TreeView items on click