element-plus 在vue3 中不生效的原因解决方法(element-plus引入)

import 'element-plus/theme-chalk/index.css' 					   //默认css样式 英文
import Element from 'element-plus'              				   //引入插件
import zhCn from 'element-plus/es/locale/lang/zh-cn'               //引入中文包

 //全局 使用element-plus  
																   //中文使用
 createApp(App).use(Element,{locale:zhCn}).mount('#app')
																   //默认英文使用
  createApp(App).use(Element).mount('#app')

import { createApp } from 'vue'
import App from './App.vue'
import router from './router'
import ElementPlus from 'element-plus';
import 'element-plus/lib/theme-chalk/index.css';

const app = createApp(App)
app.use(ElementPlus)
app.use(router).mount('#app')

  <el-tree
          ref="elTreeRef"
          :data="menus"
          show-checkbox
          node-key="id"
          :props="{ children: 'children', label: 'name' }"
          @check="handleCheckChange"
        >

import { ElTree } from 'element-plus'

 const elTreeRef = ref<InstanceType<typeof ElTree>>()
    const editCallback = (item: any) => {
      const leafKeys = menuMapLeafKeys(item.menuList)
      nextTick(() => {
        console.log(elTreeRef.value)
        elTreeRef.value?.setCheckedKeys(leafKeys, false)
      })
    }