el-select 使用

el-select动态获取数据， 默认选中第一个

<el-select
	v-model="formData.operator_id"
	placeholder="请选择"
	class="filter-item"
	style="width: 130px"> 
	  <el-option
	    v-for="item in operatorLists"
	    :key="item.key"
	    :label="item.operator_name"
	    :value="item.id"/>  
</el-select>

this.formData.operator_id = this.operatorLists[0].id 这句要加在动态获取了列表之后，如下：

OperatorSelect() {
		this.operatorSelect()
			.then(res => {
				this.operatorLists=res.data
				this.formData.operator_id = this.operatorLists[0].id
			})
			.catch(err => {
				this.$message.error(err.message)
			})
	},

第二种情况：
el-select静态获取数据， 默认选中第一个

<el-select
		v-model="formData.status"
		placeholder="请选择"
		class="filter-item"
		style="width: 130px"> 
		 <el-option
		    v-for="item in statusLists"
		    :key="item.key"
		    :label="item.status_name"
		    :value="item.id" />  
	</el-select>

  data() {
    return {
	  statusLists:[{id:1,status_name:'上线'},{id:2,status_name:'下线'}]
    }
  },
  created() {
	this.formData.status = this.statusLists[0].id
  },