# 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 ::: ## Attributes | Attribute | 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 | custome tree node icon | string | - | ## props | Attribute | Description | Type | Default | | --------- | ------------------------------------------------------------------------------------ | -------------- | -------- | | id | 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 | boolean | disabled | ## 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) | | 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) | | 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) | ## Events | Event Name | Description | Parameters | | ---------------- | ---------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------- | | node-click | triggers when a node is clicked | (data: TreeNodeData, node: TreeNode) | | 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) | ## Slots | Name | Description | | ---- | -------------------------------------------------------------------------------------------- | | — | Custom content for tree nodes. The scope parameter is { node: TreeNode, data: TreeNodeData } |