select下拉框数据过长时显示省略号，鼠标移入显示全部文字

<el-select v-model="queryParams.sjnrbm" popper-class="sjnrxl" placeholder="请选择" clearable size="small" @change="handleQuery">
　　<el-option v-for="dict in sjnrOptions" :key="dict.dictValue" :title="dict.dictLabel" :label="dict.dictLabel" :value="dict.dictValue" />
</el-select>

.sjnrxl {
  .el-select-dropdown__item {
    span {
      max-width: 170px;
      display: inline-block;
      overflow: hidden;
      text-overflow: ellipsis;
      white-space: nowrap;
    }
  }
}