# Tree Select

Source: https://lumeo.nativ.sh/components/tree-select

# Tree Select

A dropdown selector with a hierarchical tree structure — ideal for selecting categories, org chart nodes, or nested data.

## Installation

.NET CLI PackageReference Lumeo CLI

dotnet add package Lumeo

One-time app setup (`AddLumeo()`, CSS & JS) is covered in the [installation guide](docs/introduction).

## Usage

@using Lumeo

<TreeSelect />

Preview Code

Basic Tree Select

Select…

Selected: none

Preview Code

Searchable

Select…

Preview Code

Multi-select

Select…

Selected:

Preview Code

Expand All

Select…

Preview Code

With Disabled Items

Select…

## API Reference

### TreeSelect

Property

Type

Default

Description

Value

string?

—

The selected item value (single-select mode). Supports two-way binding.

Values

List<string>?

—

Selected item values (multi-select mode). Supports two-way binding.

Items

List<TreeSelectItem>

\[\]

The tree data. Each item can have Children for nesting.

Placeholder

string

"Select..."

Placeholder shown when no value is selected.

Searchable

bool

false

Enable a search box at the top of the dropdown.

Multiple

bool

false

Allow selecting multiple items (use Values/ValuesChanged).

ExpandAll

bool

false

Expand all nodes by default when the dropdown opens.

Disabled

bool

false

Disable the select control.

ValueChanged

EventCallback<string>

—

Two-way binding callback (single-select mode).

ValuesChanged

EventCallback<List<string>?>

—

Two-way binding callback (multi-select mode).

Required

bool

false

Marks the field as required. Syncs with a parent FormField.

Invalid

bool

false

Applies error styling. Syncs with a parent FormField.

ErrorText

string?

null

Error message displayed below the field when Invalid is true.

HelperText

string?

null

Helper text shown below the field when not invalid.

Label

string?

null

Label rendered above the field (standalone, without FormField).

Name

string?

null

HTML name attribute for form submission.

FormField

FormField.FormFieldContext?

null

Cascaded context from a parent FormField; wires label, validation, and required state automatically.

### TreeSelectItem

Property

Type

Description

Label

string

Display text for the node.

Value

string

Unique value for the node used in selection.

Children

List<TreeSelectItem>?

Child nodes for nested tree structure.

Disabled

bool

Prevent this node from being selected.

Icon

string?

Optional icon shown before the label.