目录
在前端开发中,级联选择框是经常用到的,这样不仅可以增加用户输入的友好性,还能减少前后端交互的数据量。本文以elementUI为例,使用其余UI组件大致思想也都相同。
1.数据库设计
所有的相关数据皆可存在一张表中,这样数据就可以不受层级的限制。
表结构可以参考如下建表SQL:
CREATE TABLE `supplies_type` ( `id` int(11) NOT NULL AUTO_INCREMENT, `category_type` varchar(64) NOT NULL COMMENT \'类别种类:大类、中类、小类\', `big_category_name` varchar(64) NOT NULL COMMENT \'大类名称\', `middle_category_name` varchar(64) DEFAULT NULL COMMENT \'中类名称\', `small_category_name` varchar(64) DEFAULT NULL COMMENT \'小类名称\', `parent_id` int(11) DEFAULT NULL, `create_time` timestamp NULL DEFAULT CURRENT_TIMESTAMP, `create_user_name` varchar(64) DEFAULT NULL COMMENT \'创建人用户名\', `update_time` timestamp NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP, `is_deleted` tinyint(1) DEFAULT \'0\' COMMENT \'是否删除,1表示已删除\', PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8mb4;
数据库截图如下图所示,注:本系统为了减少查询次数,故冗余了一些字段,读者可根据自己的需求调整。
核心设计在于parent_id,根据parent_id字段即可查询到子类,结果如下图所示:
2.前端页面
前端页面效果如下:
Html代码如下:
<div class=\"app-container\"> <span style=\"margin-left:120px;margin-right: 20px;width: 150px;display: inline-block;\">大类:</span> <el-select v-model=\"big\" placeholder=\"请选择\" @change=\"getSuppliesType(big)\" style=\"width: 19%;\"> <el-option v-for=\"item in bigTypes\" :key=\"item.bigCategoryName\" :label=\"item.bigCategoryName\" :value=\"item.id\"> </el-option> </el-select> <span style=\"margin-left:120px;margin-right: 20px; width: 150px;display: inline-block;\">中类:</span> <el-select v-model=\"middle\" placeholder=\"请选择\" @change=\"getSuppliesType(middle)\" style=\"width: 19%;\"> <el-option v-for=\"item in middleTypes\" :key=\"item.middleCategoryName\" :label=\"item.middleCategoryName\" :value=\"item.id\"> </el-option> </el-select> <br> <br> <br> <span style=\"margin-left:120px;margin-right: 20px;width: 150px; margin-top:20px; display: inline-block;\">小类:</span> <el-select v-model=\"small\" placeholder=\"请选择\" style=\"width: 19%;\"> <el-option v-for=\"item in smallTypes\" :key=\"item.smallCategoryName\" :label=\"item.smallCategoryName\" :value=\"item.id\"> </el-option> </el-select> </div>
上面的item.smallCategoryName、item.smallCategoryName数据为后端从数据库中查询出来的数据(驼峰命名),后端只负责查询、并返回结果。
Vue中数据定义如下:
data() { return { big: \'\', bigTypes: null, middle: \'\', middleTypes: null, small: \'\', smallTypes: null } },
在页面初始化时,自动获取大类列表:
created() { this.getSuppliesType(0) },
页面中的getSuppliesType方法如下:
getSuppliesType(id) { this.listLoading = true const queryData = { parentId: id } //此处的调用后端接口按照自己的调用方式写即可 //此处的getSuppliersType是项目中自己封装的util中的方法 //如果请求方式是post,JSON.stringify(queryData) //如果请求方式是get,queryData getSuppliersType(JSON.stringify(queryData)).then(response => { console.log(response) console.log(response.data[0].categoryType) //根据type自动向三个下拉框赋值 if (response.data[0].categoryType === \'BIG\') { this.bigTypes = response.data } else if (response.data[0].categoryType === \'MIDDLE\') { this.middleTypes = response.data } else { this.smallTypes = response.data } this.listLoading = false }).catch(function (error) { console.log(error) this.listLoading = false }) },
3.一个完整的demo
下面这个页面为完成代码,其中的数据为部分数据,后台接口获取使用JS来完成。
<template> <div class=\"app-container\"> <span style=\"margin-left:120px;margin-right: 20px;width: 150px;display: inline-block;\">大类:</span> <el-select v-model=\"big\" placeholder=\"请选择\" @change=\"getSuppliesType(big)\" style=\"width: 19%;\"> <el-option v-for=\"item in bigTypes\" :key=\"item.bigCategoryName\" :label=\"item.bigCategoryName\" :value=\"item.id\"> </el-option> </el-select> <span style=\"margin-left:120px;margin-right: 20px; width: 150px;display: inline-block;\">中类:</span> <el-select v-model=\"middle\" placeholder=\"请选择\" @change=\"getSuppliesType(middle)\" style=\"width: 19%;\"> <el-option v-for=\"item in middleTypes\" :key=\"item.middleCategoryName\" :label=\"item.middleCategoryName\" :value=\"item.id\"> </el-option> </el-select> <br> <br> <br> <span style=\"margin-left:120px;margin-right: 20px;width: 150px; margin-top:20px; display: inline-block;\">小类:</span> <el-select v-model=\"small\" placeholder=\"请选择\" style=\"width: 19%;\"> <el-option v-for=\"item in smallTypes\" :key=\"item.smallCategoryName\" :label=\"item.smallCategoryName\" :value=\"item.id\"> </el-option> </el-select> <br> <br> <br> <el-button type=\"primary\" round style=\"margin-left:280px\" @click.native.prevent=\"commit\">添加</el-button> <el-button type=\"primary\" round style=\"margin-left:100px\" @click.native.prevent=\"cancel\">取消</el-button> </div> </template> <script> export default { filters: { parseTime(timestamp) { return parseTime(timestamp, null) } }, data() { return { big: \'\', bigTypes: null, middle: \'\', middleTypes: null, small: \'\', smallTypes: null, dataList: [ {\"id\":1,\"categoryType\":\"BIG\",\"bigCategoryName\":\"1.现场管理与保障\",\"middleCategoryName\":null,\"smallCategoryName\":null,\"parentId\":0,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":\"2021-07-04T13:34:31.000+0000\",\"isDeleted\":false}, {\"id\":27,\"categoryType\":\"BIG\",\"bigCategoryName\":\"2.生命救援与生活救助\",\"middleCategoryName\":null,\"smallCategoryName\":null,\"parentId\":0,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":2,\"categoryType\":\"MIDDLE\",\"bigCategoryName\":\"1.现场管理与保障\",\"middleCategoryName\":\"1.1现场监测\",\"smallCategoryName\":null,\"parentId\":1,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":10,\"categoryType\":\"MIDDLE\",\"bigCategoryName\":\"1.现场管理与保障\",\"middleCategoryName\":\"1.2现场安全\",\"smallCategoryName\":null,\"parentId\":1,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":3,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"1.现场管理与保障\",\"middleCategoryName\":\"1.1现场监测\",\"smallCategoryName\":\"1.1.1气象监测\",\"parentId\":2,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":4,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"1.现场管理与保障\",\"middleCategoryName\":\"1.1现场监测\",\"smallCategoryName\":\"1.1.2地震监测\",\"parentId\":2,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":5,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"1.现场管理与保障\",\"middleCategoryName\":\"1.1现场监测\",\"smallCategoryName\":\"1.1.3地质灾害监测\",\"parentId\":2,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":6,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"1.现场管理与保障\",\"middleCategoryName\":\"1.1现场监测\",\"smallCategoryName\":\"1.1.4水文监测\",\"parentId\":2,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":7,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"1.现场管理与保障\",\"middleCategoryName\":\"1.1现场监测\",\"smallCategoryName\":\"1.1.5环境监测\",\"parentId\":2,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":8,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"1.现场管理与保障\",\"middleCategoryName\":\"1.1现场监测\",\"smallCategoryName\":\"1.1.6疫病监测\",\"parentId\":2,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":9,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"1.现场管理与保障\",\"middleCategoryName\":\"1.1现场监测\",\"smallCategoryName\":\"1.1.7观察测量\",\"parentId\":2,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":11,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"1.现场管理与保障\",\"middleCategoryName\":\"1.2现场安全\",\"smallCategoryName\":\"1.2.1现场照明\",\"parentId\":10,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":12,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"1.现场管理与保障\",\"middleCategoryName\":\"1.2现场安全\",\"smallCategoryName\":\"1.2.2现场警戒\",\"parentId\":10,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":28,\"categoryType\":\"MIDDLE\",\"bigCategoryName\":\"2.生命救援与生活救助\",\"middleCategoryName\":\"2.1人员安全防护\",\"smallCategoryName\":null,\"parentId\":27,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":34,\"categoryType\":\"MIDDLE\",\"bigCategoryName\":\"2.生命救援与生活救助\",\"middleCategoryName\":\"2.2生命搜救与营救\",\"smallCategoryName\":null,\"parentId\":27,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":\"2021-07-04T13:03:23.000+0000\",\"isDeleted\":false}, {\"id\":29,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"2.生命救援与生活救助\",\"middleCategoryName\":\"2.1人员安全防护\",\"smallCategoryName\":\"2.1.1卫生防疫\",\"parentId\":28,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":30,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"2.生命救援与生活救助\",\"middleCategoryName\":\"2.1人员安全防护\",\"smallCategoryName\":\"2.1.2消防防护\",\"parentId\":28,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":31,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"2.生命救援与生活救助\",\"middleCategoryName\":\"2.1人员安全防护\",\"smallCategoryName\":\"2.1.3化学与放射\",\"parentId\":28,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":32,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"2.生命救援与生活救助\",\"middleCategoryName\":\"2.1人员安全防护\",\"smallCategoryName\":\"2.1.4防高空坠落\",\"parentId\":28,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":33,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"2.生命救援与生活救助\",\"middleCategoryName\":\"2.1人员安全防护\",\"smallCategoryName\":\"2.1.5通用防护\",\"parentId\":28,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":35,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"2.生命救援与生活救助\",\"middleCategoryName\":\"2.2生命搜救与营救\",\"smallCategoryName\":\"2.2.1生命搜索\",\"parentId\":34,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":36,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"2.生命救援与生活救助\",\"middleCategoryName\":\"2.2生命搜救与营救\",\"smallCategoryName\":\"2.2.2攀岩营救\",\"parentId\":34,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":37,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"2.生命救援与生活救助\",\"middleCategoryName\":\"2.2生命搜救与营救\",\"smallCategoryName\":\"2.2.3破拆起重\",\"parentId\":34,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":38,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"2.生命救援与生活救助\",\"middleCategoryName\":\"2.2生命搜救与营救\",\"smallCategoryName\":\"2.2.4水下营救\",\"parentId\":34,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false}, {\"id\":39,\"categoryType\":\"SMALL\",\"bigCategoryName\":\"2.生命救援与生活救助\",\"middleCategoryName\":\"2.2生命搜救与营救\",\"smallCategoryName\":\"2.2.5通用工具\",\"parentId\":34,\"createTime\":\"2021-07-04T11:13:36.000+0000\",\"createUserName\":null,\"updateTime\":null,\"isDeleted\":false} ] } }, created() { this.getSuppliesType(0) }, methods: { getSuppliesType(id) { const queryData = { parentId: id } //此处为js模拟,真实数据的获取还需要后台接口的支持 getSuppliersType(JSON.stringify(queryData)).then(response => { console.log(response) console.log(response.data[0].categoryType) //存放此次查询结果 let tmpList = [] this.dataList.forEach((item, index) => { if(item.parentId === id){ tmpList.push(item) } }) if (tmpList[0].categoryType === \'BIG\') { this.bigTypes = tmpList } else if (response.data[0].categoryType === \'MIDDLE\') { this.middleTypes = tmpList } else { this.smallTypes = tmpList } }).catch(function (error) { console.log(error) }) }, commit() { console.log(\"点击了提交按钮\") }, cancel() { this.$router.go(-1) } } } </script>
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