Vue element ui 多层嵌套表单验证

1.html

<el-form  ref="expenseApplyForm" :model="expenseApplyData" :rules="expenseApplyRules" label-width="160px">
    <el-form-item label="单号" prop="">
        <el-input v-model="expenseApplyData.orderId" :disabled="true" placeholder="系统自动生成"></el-input>
    </el-form-item>
    <el-form-item label="项目号" prop="projectId">
        <el-input v-model="expenseApplyData.projectId" placeholder="请填入项目号"></el-input>
    </el-form-item>
    <el-form-item label="报销人" prop="expenseAccount">
        <el-input v-model="expenseApplyData.expenseAccount" placeholder="请选择报销人"></el-input>
    </el-form-item>
    <div v-for="(item,index) in expenseApplyData.expenseDetailList " >
        <el-tag type="info" style="margin-left: 160px;margin-bottom: 2px">报销明细{
 {index+1}}</el-tag>
        <el-link type="primary" v-if="expenseApplyData.expenseDetailList.length > 1" style="float: right;margin-right:19%;" @click="deleteExpenseDetail(index)">删除</el-link>
        <el-form-item label="费用事由" >
            <el-select v-model