vue Element动态设置el-menu导航当前选中项

import Vue from 'vue'
import Vuex from 'vuex'
Vue.use(Vuex)

const state = {
    count: 0,
    adminleftnavnum:"/"  //管理后台左侧导航
}
const mutations = {
    increment (state) {
        state.count++
    }  
}
// const actions = {...}
//注册Store
export default new Vuex.Store({
    state,
    mutations
});

new Vue({
  el: '#app',
  router,
  store,
  template: '<App/>',
  components: { App }
})

<el-menu :default-active="navselected" :active="navselected" @select="selectItems" class="el-menu-admin" router>

    export default {
        components:{
            'el-menu':Menu,
            'el-submenu':Submenu,
            'el-menu-item':MenuItem,
            'el-menu-item-group':MenuItemGroup
        },
        data () {
            return {
                navselected:"/",
                openends:['1','2','3','4','5','6']//默认menu展开
            }
        },
        mounted(){
            console.log(this.navselected)   
        },
        methods:{
            getNavType(){
                this.navselected=this.$store.state.adminleftnavnum;
                //store.state.adminleftnavnum里值变化的时候，设置navselected
            },
            selectItems(index){
                console.log(index)
                this.$store.state.adminleftnavnum=index;
               //按钮选中之后设置当前的index为store里的值。
            }
        },
        watch: {
            // 监测store.state
            '$store.state.adminleftnavnum': 'getNavType'
        }
    }

export default {
        created () {
            this.$store.state.adminleftnavnum="2-2"; //设置左侧导航2-2 active
        }
    }