如何在 Vue 中使用 Element UI 实现动态下拉框的表格？

<el-table :data="tabledata">
  <el-table-column v-for="item in tablecolumns" :prop="item.prop" :label="item.label">
    template: (scope) => {
      if (scope.$index === 0) {
        return <el-select v-model="scope.row[item.prop]" placeholder="请选择">
          <el-option v-for="option in dropdownoptions" :label="option.label" :value="option.value"></el-option>
        </el-select>
      } else {
        return <span>{{ scope.row[item.prop] }}</span>
      }
    }
  </el-table-column>
  <el-table-column align="right" label="操作">
    template: (scope) => {
      if (scope.$index === 0) {
        return <el-button type="primary" size="small" @click="save()">保存</el-button>
      }
      return <el-button type="danger" size="small" @click="deleterow(scope.$index)">删除</el-button>
    }
  </el-table-column>
</el-table>

save() {
  if (this.tableData[0].name && this.tableData[0].age) {
    this.tableData.push({
      name: '',
      age: ''
    })
  }
}