element-ui-解决下拉框数据量过多问题（vue-virtual-scroll-list）_element-ui下拉框数据太多如何优化-CSDN博客
的升级版
参考链接：封装el-select，实现虚拟滚动,可单选、多选、搜索查询、创建条目-CSDN博客
1.封装组件
select.vue
<template><div><el-selectpopper-class="virtualselect"class="virtual-select-custom-style":popper-append-to-body="false":value="defaultValue"filterable:filter-method="filterMethod"default-first-optionclearable:placeholder="placeholderParams":multiple="isMultiple":allow-create="allowCreate"@visible-change="visibleChange"v-on="$listeners"@clear="clearChange"><virtual-listref="virtualList"class="virtualselect-list":data-key="value":data-sources="selectArr":data-component="itemComponent":keeps="keepsParams":extra-props="{label: label,value: value,isRight: isRight,isConcat: isConcat,concatSymbol: concatSymbol}"></virtual-list></el-select></div></template><script>import {validatenull} from '@/utils'import virtualList from 'vue-virtual-scroll-list'import ElOptionNode from './el-option-node'export default {components: {'virtual-list': virtualList},model: {prop: 'bindValue',event: 'change'},props: {// // 父组件传的值// selectData: {// type: Object,// default() {// return {}// }// },// 数组list: {type: Array,default() {return []}},// 显示名称label: {type: String,default: ''},// 标识value: {type: String,default: ''},// 是否拼接label | valueisConcat: {type: Boolean,default: false},// 拼接label、value符号concatSymbol: {type: String,default: ' | '},// 显示右边isRight: {type: Boolean,default: false},// 加载条数keepsParams: {type: Number,default: 10},// 绑定的默认值bindValue: {type: [String, Array],default() {if (typeof this.bindValue === 'string') return ''return []}},// 是否多选isMultiple: {type: Boolean,default: false},placeholderParams: {type: String,default: '请选择'},// 是否允许创建条目allowCreate: {type: Boolean,default: false}},data() {return {itemComponent: ElOptionNode,selectArr: [],defaultValue: null // 绑定的默认值}},watch: {'list'() {this.init()},bindValue: {handler(val, oldVal) {this.defaultValue = this.bindValueif (validatenull(val)) this.clearChange()this.init()},immediate: false,deep: true}},mounted() {this.defaultValue = this.bindValuethis.init()},methods: {init() {if (!this.defaultValue || this.defaultValue?.length === 0) {this.selectArr = this.list} else {// 回显问题// 由于只渲染固定keepsParams（10）条数据,当默认数据处于10条之外,在回显的时候会显示异常// 解决方法:遍历所有数据,将对应回显的那一条数据放在第一条即可this.selectArr = JSON.parse(JSON.stringify(this.list))let obj = {}if (typeof this.defaultValue === 'string' && !this.isMultiple) {if (this.allowCreate) {const arr = this.selectArr.filter(val => {return val[this.value] === this.defaultValue})if (arr.length === 0) {const item = {}// item[this.value] = `Create-${this.defaultValue}`item[this.value] = this.defaultValueitem[this.label] = this.defaultValueitem.allowCreate = truethis.selectArr.push(item)this.$emit('selChange', item)} else {this.$emit('selChange', arr[0])}}// 单选for (let i = 0; i < this.selectArr.length; i++) {const element = this.selectArr[i]if (element[this.value]?.toLowerCase() === this.defaultValue?.toLowerCase()) {obj = elementthis.selectArr?.splice(i, 1)break}}this.selectArr?.unshift(obj)} else if (this.isMultiple) {if (this.allowCreate) {this.defaultValue.map(v => {const arr = this.selectArr.filter(val => {return val[this.value] === v})if (arr?.length === 0) {const item = {}// item[this.value] = `Create-${v}`item[this.value] = vitem[this.label] = vitem.allowCreate = truethis.selectArr.push(item)this.$emit('selChange', item)} else {this.$emit('selChange', arr[0])}})}// 多选for (let i = 0; i < this.selectArr.length; i++) {const element = this.selectArr[i]this.defaultValue?.map(val => {if (element[this.value]?.toLowerCase() === val?.toLowerCase()) {obj = elementthis.selectArr?.splice(i, 1)this.selectArr?.unshift(obj)}})}}}},// 搜索filterMethod(query) {if (!validatenull(query?.trim())) {this.$refs.virtualList.scrollToIndex(0) // 滚动到顶部setTimeout(() => {this.selectArr = this.list.filter(item => {return this.isRight || this.isConcat? (item[this.label].trim()?.toLowerCase()?.indexOf(query?.trim()?.toLowerCase()) > -1 || item[this.value]?.toLowerCase()?.indexOf(query?.trim()?.toLowerCase()) > -1): item[this.label]?.toLowerCase()?.indexOf(query?.trim()?.toLowerCase()) > -1})}, 100)} else {setTimeout(() => {this.init()}, 100)}},visibleChange(bool) {if (!bool) {this.$refs.virtualList.reset()this.init()}},clearChange() {if (typeof this.defaultValue === 'string') {this.defaultValue = ''} else if (this.isMultiple) {this.defaultValue = []}this.visibleChange(false)}}}</script>
<style lang="scss" scoped>.virtualselect {// 设置最大高度&-list {max-height:245px;overflow-y:auto;}.el-scrollbar .el-scrollbar__bar.is-vertical {width: 0;}}</style>el-option-node.vue
<template><el-option:key="label+value":label="concatString(source[label], source[value])":value="source[value]":disabled="source.disabled":title="concatString(source[label], source[value])"><span>{{ concatString(source[label], source[value]) }}</span><spanv-if="isRight"style="float:right;color:#939393">{{ source[value] }}</span></el-option></template><script>export default {name: 'ItemComponent',props: {// 每一行的索引index: {type: Number,default: 0},// 每一行的内容source: {type: Object,default() {return {}}},// 需要显示的名称label: {type: String,default: ''},// 绑定的值value: {type: String,default: ''},// 是否拼接label | valueisConcat: {type: Boolean,default: false},// 拼接label、value符号concatSymbol: {type: String,default: ' | '},// 右侧是否显示绑定的值isRight: {type: Boolean,default() {return false}}},methods: {concatString(a, b) {a = a || ''b = b || ''if (this.isConcat) {// return a + ((a && b) ? ' | ' : '') + breturn a + ((a && b) ? this.concatSymbol : '') + b}return a}}}</script>2.使用：
第一层组件：insuplc.vue
<template><cw-selectv-model="value":list="list"label="name"value="value":class="classname" :disabled="disabled" :placeholder-params="placeholder":keeps-params="10":is-concat="false":is-multiple="isMultiple":is-right="false":allow-create="false"@change="selectChange"/>
</template><script>import CwSelect from '@/components/virtualScrollList/select.vue'export default {name:'insuplc',components: {CwSelect},props: {isMultiple: {type: Boolean,default: false},defaultValue: {},disabled: {type: Boolean},classname: {type: Object},placeholder: {type: String},},computed: {insuplcList() {//医保区划return this.$store.state.app.ybDictMap.yb_insuplc},},watch: {defaultValue:{handler(newVal) {this.value = newVal},immediate: true,deep: true}},data() {return {value:this.defaultValue,list:[]};},mounted() {this.list = JSON.parse(JSON.stringify(this.insuplcList))},methods: {selectChange(val) {this.$emit('change', {value:val})}}};
</script>第二层：
<insuplc :isMultiple="true" style="display:inline-block;width: 100%;" placeholder='请选择' :defaultValue="form.insuplc" @change="(val) => changeInsuplc(val)" />
