首先要在标签上定义ref="xxx"

然后可以在代码中调用

this.$refs.xxx

<el-tree
            style="     background: rgba(33, 43, 53, 0.2);
                color: white;
                height: 250px;
                overflow-y: auto;
                font-size: 14px;"
            class="filter-tree"
            :render-after-expand="false"
            default-expand-all
            show-checkbox
            node-key="id"
            :data="data"
            :props="defaultProps"
            :filter-node-method="filterNode"
            :expand-on-click-node="true"
            @check-change="layerTreeCheckChanged"
            @node-contextmenu="rightClick"
            @node-click="nodeClick"
            ref="tree">

数据绑定：data

          this.$nextTick(_=>{
              setTimeout(_=>{
                tree.setChecked(this.rightNode,true,true);
              },500)
           })

this.$nextTick()和tree.setChecked()两个事件会触发什么？

tree.setChecked()会触发tree的check-change事件。。

parseMsg->drawPoint
怎么执行的呢？
是由EventBus.$emit("queryTrack",str)发送
然后this.ws2.send(sql)
ws2接收到消息之后，又发送UDP信息
on("UDP",)
执行parseMsg。。调用drawPoint