Vue级联下拉框的设计和实现方法

这篇文章主要介绍“Vue级联下拉框的设计和实现方法”，在日常操作中，相信很多人在Vue级联下拉框的设计和实现方法问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答”Vue级联下拉框的设计和实现方法”的疑惑有所帮助！接下来，请跟着小编一起来学习吧！

目录

• 数据库设计

• 前端页面

• 一个完整的demo

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 >大类：</span>    <el-select v-model="big" placeholder="请选择" @change="getSuppliesType(big)" >      <el-option        v-for="item in bigTypes"        :key="item.biGCategoryName"        :label="item.bigCategoryName"        :value="item.id">      </el-option>    </el-select>    <span >中类：</span>    <el-select v-model="middle" placeholder="请选择" @change="getSuppliesType(middle)" >      <el-option        v-for="item in middleTypes"        :key="item.middleCategoryName"        :label="item.middleCategoryName"        :value="item.id">      </el-option>    </el-select>    <br>    <br>    <br>    <span >小类：</span>    <el-select v-model="small" placeholder="请选择" >      <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 >大类：</span>    <el-select v-model="big" placeholder="请选择" @change="getSuppliesType(big)" >      <el-option        v-for="item in bigTypes"        :key="item.bigCategoryName"        :label="item.bigCategoryName"        :value="item.id">      </el-option>    </el-select>    <span >中类：</span>    <el-select v-model="middle" placeholder="请选择" @change="getSuppliesType(middle)" >      <el-option        v-for="item in middleTypes"        :key="item.middleCategoryName"        :label="item.middleCategoryName"        :value="item.id">      </el-option>    </el-select>    <br>    <br>    <br>    <span >小类：</span>    <el-select v-model="small" placeholder="请选择" >      <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  @click.native.prevent="commit">添加</el-button>    <el-button type="primary" round  @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

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