需求说明

• 弹窗中内嵌一个 form 表单
  
• 原始代码

<script setup lang="ts">
import { reactive, ref } from "vue"
import type { FormRules } from 'element-plus'
const ruleFormRef = ref()
interface RuleForm {name: stringregion: number | null
}
const ruleForm = reactive<RuleForm>({name: '',region: null,
})
const rules = reactive<FormRules<RuleForm>>({name: [{ required: true, message: '请填写姓名', trigger: 'blur' },],region: [{ required: true, message: '请选择区域编码', trigger: 'change' },]
})
const dialogVisible = ref(false);
function handelDialogPop(type: string) {if (type == "open") {dialogVisible.value = true; // 开启弹窗} else if (type == "submit") {ruleFormRef.value.validate((valid: any, fields: any) => {if (valid) {console.log('提交成功')// 关闭弹窗ruleFormRef.value.resetFields();dialogVisible.value = false;} else {console.log('error submit!', fields)}})} else if (type == "cancel") {// 关闭弹窗ruleFormRef.value.resetFields();dialogVisible.value = false}
}
</script>
<template><div class="dataBox"><el-button type="primary" @click="handelDialogPop('open')">开启弹窗</el-button><el-dialog v-model="dialogVisible" title="弹窗" width="500"><el-form ref="ruleFormRef" :model="ruleForm" :rules="rules" label-width="auto"><el-form-item label="姓名" prop="name"><el-input v-model="ruleForm.name" /></el-form-item><el-form-item label="区域" prop="region"><el-select v-model="ruleForm.region" placeholder="区域编码"><el-option label="第一区" :value="1" /><el-option label="第二区" :value="2" /></el-select></el-form-item></el-form><template #footer><div class="dialog-footer"><el-button type="primary" plain @click="handelDialogPop('cancel')">取消</el-button><el-button type="primary" @click="handelDialogPop('submit')">提交</el-button></div></template></el-dialog></div>
</template>

• 点击取消按钮，或者提交通过校验时，先执行了 form 表单的 resetFields 事件。此代码会将表单的值重置为初始值，并且移除所有校验。这样可以保证下次点开弹窗时，不会保留上次操作 form 的痕迹。
  
• 为了省事儿，我把所有对 dialog 的操作都写进了 handelDialogPop 函数里，传入 type 来区分是什么事件（这里就是出问题的关键）

发现问题

• 手动点击关闭按钮，或者点击 model 空白区域时，弹窗被关闭。未执行 form 表单的 resetFields 方法，所以再次打开时，弹窗保留了上次操作的痕迹（form 表单未重置）
  

• 因此需要监听 dialog 的关闭事件，官方提供了一个方法，before-close
  

<el-dialog v-model="dialogVisible" title="弹窗" width="500" :before-close="handelDialogPop('cancel')">
...

• 问题出现了，一进入页面时，直接抛错。报错信息可看出，before-close 被触发了

问题解决

• 文档中表明，before-close 传参，done 说明会执行。
  
• 重新为 before-close 封装一个函数

完整代码

<script setup lang="ts">
import { reactive, ref } from "vue"
import type { FormRules } from 'element-plus'
const ruleFormRef = ref()
interface RuleForm {name: stringregion: number | null
}
const ruleForm = reactive<RuleForm>({name: '',region: null,
})
const rules = reactive<FormRules<RuleForm>>({name: [{ required: true, message: '请填写姓名', trigger: 'blur' },],region: [{ required: true, message: '请选择区域编码', trigger: 'change' },]
})
const dialogVisible = ref(false);
function beforeCloseDialog() {console.log("执行了 beforeCloseDialog");ruleFormRef.value.resetFields();dialogVisible.value = false
}
function handelDialogPop(type: string) {if (type == "open") {dialogVisible.value = true} else if (type == "submit") {ruleFormRef.value.validate((valid: any, fields: any) => {if (valid) {console.log('提交成功')beforeCloseDialog();} else {console.log('error submit!', fields)}})} else if (type == "cancel") {// 关闭弹窗beforeCloseDialog()}
}
</script>
<template><div class="dataBox"><el-button type="primary" @click="handelDialogPop('open')">开启弹窗</el-button><el-dialog v-model="dialogVisible" title="弹窗" width="500" :before-close="beforeCloseDialog"><el-form ref="ruleFormRef" :model="ruleForm" :rules="rules" label-width="auto"><el-form-item label="姓名" prop="name"><el-input v-model="ruleForm.name" /></el-form-item><el-form-item label="区域" prop="region"><el-select v-model="ruleForm.region" placeholder="区域编码"><el-option label="第一区" :value="1" /><el-option label="第二区" :value="2" /></el-select></el-form-item></el-form><template #footer><div class="dialog-footer"><el-button type="primary" plain @click="handelDialogPop('cancel')">取消</el-button><el-button type="primary" @click="handelDialogPop('submit')">提交</el-button></div></template></el-dialog></div>
</template>