element-ui 表格树形结构的全选不能选中children

问题描述：

element-ui table树形结构添加多选时，点击全选只能选中第一级的行，无法选中子级

---

解决方案：

完整代码如下：

<template>
  <div>
    <el-table
      ref="multipleTable"
      :data="tableData"
      row-key="id"
      :tree-props="{ children: 'children', hasChildren: 'hasChildren' }"
      @select-all="selectAll"
    >
      <el-table-column type="selection" width="55"> </el-table-column>
      <el-table-column prop="date" label="日期" sortable width="180">
      </el-table-column>
      <el-table-column prop="name" label="姓名" sortable width="180">
      </el-table-column>
      <el-table-column prop="address" label="地址"> </el-table-column>
    </el-table>
  </div>
</template>
<script>
export default {
  data() {
    return {
      tableData: [
        {
          id: 1,
          date: "2016-05-02",
          name: "王小虎",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          id: 2,
          date: "2016-05-04",
          name: "王小虎",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          id: 3,
          date: "2016-05-01",
          name: "王小虎",
          address: "上海市普陀区金沙江路 1519 弄",
          children: [
            {
              id: 31,
              date: "2016-05-01",
              name: "王小虎",
              address: "上海市普陀区金沙江路 1519 弄",
            },
            {
              id: 32,
              date: "2016-05-01",
              name: "王小虎",
              address: "上海市普陀区金沙江路 1519 弄",
            },
          ],
        },
        {
          id: 4,
          date: "2016-05-03",
          name: "王小虎",
          address: "上海市普陀区金沙江路 1516 弄",
        },
      ],
      checkedKeys: false,
    };
  },
  methods: {
    selectAll() {
      this.checkedKeys = !this.checkedKeys;
      this.select(this.tableData, this.checkedKeys);
    },
    select(data, flag) {
      data.forEach((row) => {
        this.$refs.multipleTable.toggleRowSelection(row, flag);
        if (row.children != undefined) {
          this.select(row.children, this.checkedKeys);
        }
      });
    },
  },
};
</script>