## Tree Display information can be unfolded or folded in a clear hierarchy. ### How to use Display the basic tree structure. ::: demo ```html ``` ::: ### Options Used for level selection. In the following example, the layer data is unpredictable when the data is clicked(ps: the data is acquired when clicked the current layer). If there is no lower layer data, the pull-down button is disappeared. ::: demo ```html ``` ::: ### Attributes | Attribute | Description | Type | Options | Default | |---------- |-------------- |---------- |-------------------------------- |-------- | | data | Show the data | array | — | — | | props | Configuration options, to see the following table | object | — | — | | load | Method for loading subtree data | function(node, resolve) | — | — | ### props | Attribute | Description | Type | Options | Default | |---------- |-------------- |---------- |-------------------------------- |-------- | | label | Specifies that a node label is a property value of a node object | string | — | — | | children | The specified subtree is a property value of the node object | string | — | — | ### Method `Tree` has the following method, which returns the currently selected array of nodes. | Method | Description | Parameter | |---------- |-------- |---------- | | getCheckedNodes | If the node can be selected(`show-checkbox` is `true`), it returns the currently selected array of nodes | Accept a boolean type parameter whose default value is `false`.
If the parameter is `true`, it only returns the currently selected array of sub-nodes.| ### Events | Event | Description | Callback | |---------- |-------- |---------- | | node-click | Callback when the node is clicked | The instance that corresponds to the node in the array passed to the `data` property | | check-change | Callback when the selected state of the node changes | Three parameters:
The instance that corresponds to the node in the array passed to the `data` property,
whether the node itself is selected,
whether there are selected nodes in the subtree of the node|