vue省市区三联动下拉选择组件的实现

<template> <div id="app"> <h5>vue 省市区三联动 demo</h5> <city-select v-model="cityInfo"></city-select> <h6>v-model的值是 <code>{{ cityInfo }}</code></h6> <h6>从v-model得知,你选择了 <i>{{ cityName }}</i></h6> </div></template><script> import CitySelect from './components/CitySelect.vue' export default { data() { return { cityInfo: '', } }, components: { CitySelect }, computed: { cityName() { const names = []; this.cityInfo.province && names.push(this.cityInfo.province.name + ' ') this.cityInfo.city && names.push(this.cityInfo.city.name + ' ') this.cityInfo.block && names.push(this.cityInfo.block.name + ' ') return names.join('') } } }</script><style lang="stylus"> h6 padding 10px border 1px dotted h6 i color #f00 border 1px dotted #ccc</style>

<template> <div class="city-select"> <select v-model="selectedProvince" name="province"> <option v-for="(item, index) in provinces" v-if="item.level === 1" :value="item"> {{ item.name }} </option> </select> <select v-model="selectedCity" name="city"> <option v-for="(item, index) in cities" :value="item"> {{ item.name }} </option> </select> <select v-model="selectedBlock" name="block"> <option v-for="(item, index) in blocks" :value="item"> {{ item.name }} </option> </select> </div></template><script>/** * 省 市 区/县城 三联动选择器*/import provinces from './provinces.js'import Vue from 'vue'export default { name: 'app', created() { // 数据初始化,默认选中北京市,默认选中第一个;北京市数据为总数据的前18个 let beijing = this.provinces.slice(0, 19) this.cities = beijing.filter(item => { if (item.level === 2) { return true } }) this.selectedCity = this.cities[0] this.blocks = beijing.filter(item => { if (item.level === 3) { return true } }) this.selectedBlock = this.blocks[0] }, watch: { selectedProvince(newVal, oldVal) { // 港澳台数据只有一级,特殊处理 if (newVal.sheng === '71' || newVal.sheng === '81' || newVal.sheng === '82') { this.cities = [newVal] this.blocks = [newVal] } else { this.cities = this.provinces.filter(item => {  if (item.level === 2 && item.sheng && newVal.sheng === item.sheng) {  return true  } }) } var _this = this // 此时在渲染DOM,渲染结束之后再选中第一个 Vue.nextTick(() => { _this.selectedCity = _this.cities[0] _this.$emit('input', _this.info) }) }, selectedBlock() { var _this = this Vue.nextTick(() => { _this.$emit('input', _this.info) }) }, selectedCity(newVal) { // 选择了一个市,要选择区了 di是城市的代表,sheng if (newVal.sheng === '71' || newVal.sheng === '81' || newVal.sheng === '82') { this.blocks = [newVal] this.cities = [newVal] } else { this.blocks = this.provinces.filter(item => {  if (item.level === 3 && item.sheng && item.sheng == newVal.sheng && item.di === newVal.di && item.name !== '市辖区') {  return true  } }) } var _this = this Vue.nextTick(() => { _this.selectedBlock = _this.blocks[0] // 触发与 v-model相关的 input事件 _this.$emit('input', _this.info) }) } }, computed: { info() { return { province: this.selectedProvince, city: this.selectedCity, block: this.selectedBlock } } }, data() { return { selectedProvince: provinces[0], selectedCity: 0, selectedBlock: 0, cities: 0, provinces, blocks: 0 } }}</script><style lang="stylus" scoped> .city-select select outline 0</style>

Vue.nextTick(() => { _this.$emit('input', _this.info) })