el-select选择一个选项，在对应输入框填入该选项对应的id

html:
<el-select
  :ref="item.meta.system_id"
  v-model="temp[item.meta.valueKey]"
  :disabled="item.meta.disabled"
  clearable
  :placeholder="item.meta.placeholder ? item.meta.placeholder : '请选择'"
  @change="changeGrade"
>
  <template v-for="(option, _index) in item.meta.options_OBJ.data">
    <el-option :key="_index" :label="option.label" :value="option.value" />
  </template>
</el-select>

js:

changeGrade(val) {
  this.temp['gradeKey'] = val // 赋值给年级编码
},