VUE 单文件组件使用 Element-UI 的多选表格，无法实现全选框(表头的 checkbox) 与单行 checkbox 的联动

mTable.vue

<template>
  <div>
    <el-table ref="multipleTable" :data="tableData3" border tooltip-effect="dark" style="width: 100%" @selection-change="handleSelectionChange">
        <el-table-column type="selection" width="55">
        </el-table-column>
        <el-table-column label="日期" width="120">
          <template scope="scope">{{ scope.row.date }}</template>
        </el-table-column>
        <el-table-column prop="name" label="姓名" width="120">
        </el-table-column>
        <el-table-column prop="address" label="地址" show-overflow-tooltip>
        </el-table-column>
      </el-table>
      <div style="margin-top: 20px">
        <el-button @click="toggleSelection([tableData3[1], tableData3[2]])">切换第二、第三行的选中状态</el-button>
        <el-button @click="toggleSelection()">取消选择</el-button>
      </div>
  </div>
</template>

<script>
  export default {
    data () {
      return {
        tableData3: [{
          date: '2016-05-03',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        }, {
          date: '2016-05-02',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        }, {
          date: '2016-05-04',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        }, {
          date: '2016-05-01',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        }, {
          date: '2016-05-08',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        }, {
          date: '2016-05-06',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        }, {
          date: '2016-05-07',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        }],
        multipleSelection: []
      }
    },
    methods: {
      toggleSelection (rows) {
        if (rows) {
          rows.forEach(row => {
            this.$refs.multipleTable.toggleRowSelection(row)
          })
        } else {
          this.$refs.multipleTable.clearSelection()
        }
      },
      handleSelectionChange (val) {
        this.multipleSelection = val
      }
    }
  }
</script>

<style lang="css">

</style>