template部分代碼：

<el-table
    ref="multipleTable"
    :data="tableData"
    style="width: 100%"
    :row-key="(row)=>{ return row.id}"
    :reserve-selection="true"
    @selection-change="handleSelectionChange">
    <el-table-column
      type="selection"
      :reserve-selection="true"
      width="55">
    </el-table-column>
  </el-table>

 :row-key="(row)=>{ return row.id}" //給每一項(xiàng)添加一個(gè)key   做上標(biāo)記
 :reserve-selection="true"  //在數(shù)據(jù)更新之后保留之前選中的數(shù)據(jù)   這個(gè)屬性必要要結(jié)合row-key