田野里，高粱像喝醉了酒，频频点头；玉米正在变黄了的衣服里睡大觉；大豆也小坡了肚皮，蹦了出来；小白菜像列队的士兵整齐地排列在在菜地里。农民正忙忙碌碌地收获着一年的成果，田野里不时传出阵阵欢笑声。啊，秋天的景色真美啊！
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>
又到了分隔线以下，本文到此就结束了，本文内容全部都是由博主自己进行整理并结合自身的理解进行总结
到此这篇关于Vue 级联下拉框的设计与实现的文章就介绍到这了,更多相关Vue 级联下拉框 内容请搜索以前的文章或继续浏览下面的相关文章希望大家以后多多支持！
