z_element_plus/docs/en-US/component/tree-v2.md

---

title: Virtualized Tree

lang: en-US

Tree V2 virtualized tree

Tree view with blazing fast scrolling performance for any amount of data

Basic usage

Basic tree structure.

:::demo

tree-v2/basic

:::

Selectable

Used for node selection.

:::demo

tree-v2/selectable

:::

Disabled checkbox

The checkbox of a node can be set as disabled.

:::demo In the example, disabled property is declared in defaultProps, and some nodes are set as disabled: true. The corresponding checkboxes are disabled and can't be clicked.

tree-v2/disabled

:::

Default expanded and default checked

Tree nodes can be initially expanded or checked

:::demo Use default-expanded-keys and default-checked-keys to set initially expanded and initially checked nodes respectively.

tree-v2/default-state

:::

Custom node content

The content of tree nodes can be customized, so you can add icons or buttons as you will

:::demo

tree-v2/custom-node

:::

Tree node filtering

Tree nodes can be filtered

:::demo Invoke the filter method of the Tree instance to filter tree nodes. Its parameter is the filtering keyword. Note that for it to work, filter-node-method is required, and its value is the filtering method.

tree-v2/filter

:::

TreeV2 Attributes

Name	Description	Type	Default
data	tree data	array	—
empty-text	text displayed when data is void	string	—
props	configuration options, see the following table	object	—
highlight-current	whether current node is highlighted	boolean	false
expand-on-click-node	whether to expand or collapse node when clicking on the node, if false, then expand or collapse node only when clicking on the arrow icon.	boolean	true
check-on-click-node	whether to check or uncheck node when clicking on the node, if false, the node can only be checked or unchecked by clicking on the checkbox.	boolean	false
default-expanded-keys	array of keys of initially expanded nodes	array	—
show-checkbox	whether node is selectable	boolean	false
check-strictly	whether checked state of a node not affects its father and child nodes when show-checkbox is true	boolean	false
default-checked-keys	array of keys of initially checked nodes	array	—
current-node-key	key of initially selected node	string / number	—
filter-method	this function will be executed on each node when use filter method. if return false, tree node will be hidden.	Function(value, data)	—
indent	horizontal indentation of nodes in adjacent levels in pixels	number	16
icon	custom tree node icon	string \| Component	-
item-size	custom tree node height	number	26

props

Attribute	Description	Type	Default
value	unique identity key name for nodes, its value should be unique across the whole tree	string, number	id
label	specify which key of node object is used as the node's label	string	label
children	specify which node object is used as the node's subtree	string	children
disabled	specify which key of node object represents if node's checkbox is disabled	string	disabled

TreeV2 Method

Tree has the following method, which returns the currently selected array of nodes. | Method | Description | Parameters | | --------------- | ---------------------------------------- | ---------------------------------------- | | filter | filter all tree nodes, filtered nodes will be hidden | (query: string) | | getCheckedNodes | If the node can be selected (show-checkbox is true), it returns the currently selected array of nodes | (leafOnly: boolean) | | getCheckedKeys | If the node can be selected (show-checkbox is true), it returns the currently selected array of node's keys | (leafOnly: boolean) | | setCheckedKeys | set certain nodes to be checked | (keys: TreeKey[]) | | setChecked | set node to be checked or not | (key: TreeKey, checked: boolean) | | setExpandedKeys | set certain nodes to be expanded | (keys: TreeKey[]) | | getHalfCheckedNodes | If the node can be selected (show-checkbox is true), it returns the currently half selected array of nodes | - | | getHalfCheckedKeys | If the node can be selected (show-checkbox is true), it returns the currently half selected array of node's keys | - | | getCurrentKey | return the highlight node's key (undefined if no node is highlighted) | - | | getCurrentNode | return the highlight node's data (undefined if no node is highlighted) | - | | setCurrentKey | set highlighted node by key | (key: TreeKey) | | getNode | get node by key or data | (data: TreeKey \| TreeNodeData) | | expandNode | expand specified node | (node: TreeNode) | | collapseNode | collapse specified node | (node: TreeNode) | | setData | When the data is very large, using reactive data will cause the poor performance, so we provide a way to avoid this situation | (data: TreeData) |

TreeV2 Events

Name	Description	Parameters
node-click	triggers when a node is clicked	(data: TreeNodeData, node: TreeNode, e: MouseEvent)
node-contextmenu	triggers when a node is clicked by right button	(e: Event, data: TreeNodeData, node: TreeNode)
check-change	triggers when the selected state of the node changes	(data: TreeNodeData, checked: boolean)
check	triggers after clicking the checkbox of a node	(data: TreeNodeData, info: { checkedKeys: TreeKey[],checkedNodes: TreeData, halfCheckedKeys: TreeKey[], halfCheckedNodes: TreeData,})
current-change	triggers when current node changes	(data: TreeNodeData, node: TreeNode)
node-expand	triggers when current node open	(data: TreeNodeData, node: TreeNode)
node-collapse	triggers when current node close	(data: TreeNodeData, node: TreeNode)

TreeV2 Slots

Name	Description
-	Custom content for tree nodes. The scope parameter is { node: TreeNode, data: TreeNodeData }