本篇内容介绍了“element中el-form-item属性prop的坑怎么解决”的有关知识,在实际案例的操作过程中,不少人都会遇到这样的困境,接下来就让小编带领大家学习一下如何处理这些情况吧!希望大家仔细阅读,能够学有所成!
最近负责前后端项目开发,有个需求是实现Djangorestframework(drf)+element实现动态渲染form表单,drf后端提供json,前端从json中获取form表单元素,并且绑定表单验证规则
在el-form-item属性prop上遇到报错或者没绑定到数据,报错如下
[Vue warn]: Error in render: "TypeError: Cannot read properties of undefined (reading 'prop')"
element官方文档解释el-form-item的prop必须是el-form属性model的直接子属性
后端返回数据如下
{ "status": "success", "code": 200, "data": { "form_attributes": { "inline": true, "label-width": "auto", "size": "small" }, "form_data": { "name": null, "path": null, "component": null, "hidden": false, "meta": { "icon": null, "title": null }, "pid": null }, "form_item_list": [ { "type": "text", "prop": "name", "label": "菜单名", "placeholder": "请输入菜单名", "rules": [ { "required": true, "message": "请输入菜单名", "trigger": "blur" } ] }, { "type": "text", "prop": "path", "label": "链接地址", "placeholder": "'/'开头", "rules": [ { "required": true, "message": "'/'开头", "trigger": "blur" } ] }, { "type": "text", "prop": "component", "label": "组件", "placeholder": "参考前端组件填写", "rules": [ { "required": true, "message": "参考前端组件填写", "trigger": "blur" } ] }, { "type": "switch", "prop": "hidden", "label": "是否隐藏", "value": false }, { "type": "json", "prop": "meta", "item": [ { "type": "text", "prop": "icon", "label": "图标", "placeholder": "图标名字,参考前端图标", "rules": [ { "required": true, "message": "图标名字,参考前端图标", "trigger": "blur" } ] }, { "type": "text", "prop": "title", "label": "", "placeholder": "请输入菜单名", "rules": [ { "required": true, "message": "请输入菜单名", "trigger": "blur" } ] } ] }, { "type": "select", "prop": "pid", "label": "父菜单", "clearable": true, "filterable": false, "multiple": false, "options": [ { "label": "系统管理", "value": 2 }, { "label": "用户管理", "value": 3 }, { "label": "菜单管理", "value": 4 }, { "label": "权限管理", "value": 5 }, { "label": "角色管理", "value": 6 } ] } ] }, "message": null}
从上面可以看到form表单元素对应的是 form_item_list,表单提交数据是 form_data,这两个是分开,也就是el-form中model绑定是 form_data 而el-form-item遍历的是 form_item_list,注意 form_item_list 中含有嵌套类型json,对应的后端是json字段渲染表单,单独提供form_data返回字段设计是为了控制前端json内容,动态字段中过于灵活,可以随意修改json包含的字段和类型,所以返回字段由后端控制和校验
截取前端渲染表单代码如下,注意这个时候能渲染但是rules绑定是失败的
<!-- 添加菜单对话框 --> <el-dialog title="添加菜单" :visible.sync="addDialogVisible" width="50%" :close-on-click-modal="false" @close="addDialogClosed"> <!-- 表单内容主体 --> <el-form ref="addFormRef" :model="formData" :size="formAttributes.size" :inline="formAttributes.inline" :label-width="formAttributes.labelWidth"> <div v-for="(item, index) in formItemList" :key="index"> <el-form-item :prop="formItemList + index + item.prop" :label="item.label" :rules="item.rules"> <!-- text输入框 --> <el-input v-if="item.type==='text'" v-model="formData[item.prop]" clearable :placeholder="item.placeholder"></el-input> <!-- textarea输入框 --> <el-input v-if="item.type==='textarea'" v-model="formData[item.prop]" clearable autosize :type="textarea" :placeholder="item.placeholder"></el-input> <!-- 下拉框 --> <el-select v-if="item.type==='select'" v-model="formData[item.prop]" clearable :multiple="item.multiple"> <el-option v-for="op in item.options" :key="op.value" :label="op.label" :value="op.value"></el-option> </el-select> <el-switch v-if="item.type==='switch'" v-model="formData[item.prop]" :label="item.label"></el-switch> <template v-if="item.type==='json'"> <div v-for="(json_item, json_index) in item.item" :key="json_index"> <el-form-item :prop="item.item + json_index + json_item.prop" :label="json_item.label" :rules="json_item.rules" > <!-- text输入框 --> <el-input v-if="json_item.type==='text'" v-model="formData[item.prop][json_item.prop]" clearable :placeholder="json_item.placeholder"></el-input> <!-- textarea输入框 --> <el-input v-if="json_item.type==='textarea'" v-model="formData[json_item.prop]" clearable autosize :type="textarea" :placeholder="json_item.placeholder"></el-input> <!-- 下拉框 --> <!-- <el-select v-if="item.type==='select'" v-model="formData[item.prop]" clearable :placeholder="item.label" :multiple="item.multiple" @change="item.change(formData[item.prop])"> --> <el-select v-if="json_item.type==='select'" v-model="formData[json_item.prop]" clearable :multiple="json_item.multiple"> <el-option v-for="op in json_item.options" :key="op.value" :label="op.label" :value="op.value"></el-option> </el-select> <el-switch v-if="json_item.type==='switch'" v-model="formData[json_item.prop]" :label="json_item.label"></el-switch> </el-form-item> </div> </template> </el-form-item> </div> </el-form> <!-- 底部 --> <el-divider></el-divider> <span slot="footer" class="dialog-footer"> <el-button @click="addDialogVisible = false">取消</el-button> <el-button type="primary" @click="addForm">确定</el-button> </span> </el-dialog>
在前端渲染无法绑定到表单规则,如下图
经过研究,从上面的数据结构可以发现,form_data 中每个元素对应是 form_item_list 中的 prop,那么有两个写法可以定位
第一种写法如下,这种写法没那么直观
<!-- 普通字段渲染 --><el-form-item :prop="item.prop" :label="item.label" :rules="item.rules"><!-- json字段渲染 --><el-form-item :prop="item.prop + '.' + json_item.prop" :label="json_item.label" :rules="json_item.rules" >
更好的第二种写法如下
<el-form-item :prop="formItemList[index].prop" :label="item.label" :rules="item.rules"><el-form-item :prop="formItemList[index].prop + '.' + item.item[json_index].prop" :label="json_item.label" :rules="json_item.rules" >
此时能动态渲染表单和绑定表单项验证规则,如下图
“element中el-form-item属性prop的坑怎么解决”的内容就介绍到这里了,感谢大家的阅读。如果想了解更多行业相关的知识可以关注编程网网站,小编将为大家输出更多高质量的实用文章!