参考:Vue2 el-select下拉框,默认选择第一个值_猫小黑呀的博客-CSDN博客_select下拉框默认选中第一个
el-select下拉框基本写法:
<el-form :inline="true" :model="formInline" class="demo-form-inline">
      <el-form-item label="名称">
        <el-select v-model="formInline.stationName" @change="onTitleChange">
          <el-option v-for="(item,index) in formInline.station" :label="item.station_name" :value="item.station_id"
                     :key="item.station_id"></el-option>
        </el-select>
      </el-form-item>
      <el-form-item>
        <el-button type="primary" icon="el-icon-search">查询</el-button>
      </el-form-item>
    </el-form>export default {
  name: 'Corporate-Contacts',
  data() {
    return {
      formInline: {
        station: [], //station_id的值
        station_Name: '', // name
        station_Id:'' // 配点站的id
      }
    }
  },
}分下下分别为三部分:
<el-form :model="formInline" class="demo-form-inline">
</el-form><el-select v-model="formInline.stationName" @change="onTitleChange">
</el-select><el-option 
    v-for="(item,index) in formInline.station" 
    :label="item.station_name" 
    :value="item.station_id"
    :key="item.station_id"
>
</el-option>第一部分是综合的model,第二部分是你选中的,第三部分下下拉要展示的
复杂的混合模式,嵌套两个下拉框:
<el-form :inline="true" :model="formInline" class="demo-form-inline">
        <el-select v-model="formInline.stationName.station_Name" @change="onTitleChange">
          <el-option v-for="(item,index) in formInline.stationName.station" :label="item.stationName.station_name" :value="item.stationName.station_id"
                     :key="item.station_id"></el-option>
        </el-select>
        <el-select v-model="formInline.TestName.name" @change="inTitleChange">
          <el-option v-for="(item,index) in formInline.TestName.station" :label="item.TestName.name" :value="item.TestName.id"
                     :key="item.station_id"></el-option>
        </el-select>
    </el-form>export default {
  name: 'Corporate-Contacts',
  data() {
    return {
      formInline: {
        stationName:[
                station: [], //station_id的值
                station_Name: '', // name
                station_Id:'' // 配点站的id
        ],
        TestName:[
                station: [], //station_id的值
                Name: '', // name
                Id:'' // 配点站的id
        ],
        
      }
    }
  },
}你想获取下拉框的所有内容,对应this.formInline.stationName和this.formInline.TestName
你想获取当前选中了哪个,this.formInline.stationName.station_Name和this.formInline.TestName.Name
默认选中第几项this.formInline.stationName[0].station_Name和this.formInline.TestName[0].Name
