javascript - The method call of the tree control in iView is wrong

Question

Official website description
Tree methods

Method name	illustrate	parameter
getCheckedNodes	Get the checked node	none
getSelectedNodes	Get the selected node	none

My own code----------------------------------

<button @click='getCheckedNodes'>获取被选中的节点</button>
<button @click="getSelectedNodes">获取被勾选的节点</button>

My own code---------------------------

getCheckedNodes(){
    console.log(this.$refs.Tree.getCheckedNodes());
},
getSelectedNodes(){
    console.log(this.$refs.tree.getSelectedNodes);
}

Error reporting

App.vue?2573:105 Uncaught TypeError: Cannot read property 'getCheckedNodes' of undefined

at VueComponent.getCheckedNodes (eval at <anonymous> (app.js:967), <anonymous>:92:40)
at boundFn (eval at <anonymous> (app.js:723), <anonymous>:125:14)
at HTMLButtonElement.invoker (eval at <anonymous> (app.js:723), <anonymous>:1659:18)

Answer 1

Tree component call should be written with ref

<Tree :data="baseData" show-checkbox ref="tree"></Tree>