需求：
利用el-cascader级联实现一级菜单单选，二级菜单多选的功能，如下图所示：
思路：
使用了多选multiply属性，这个属性下，选中的数据结构为：一级为length1的数组，二级为length2的数组。利用标识符，把最后选中的一级菜单的值与标识符做对比，如不同，则让标识符的值 = 一级菜单的值，然后新建数组，利用filter过滤出标识符与一级菜单的值相同的元素，在每次选中节点且赋值前，清空v-model，再将过滤后的数组赋值到v-model。
选择器选项：
<div class="content">
<el-cascader v-model="casValue" :props="props" :options="options" @change="change" />
</div>
数据结构：
const options = [
{
value: 1,
label: 'Asia',
children: [
{
value: 2,
label: 'China',
},
{
value: 6,
label: 'Japan',
},
{
value: 10,
label: 'Korea',
},
],
},
{
value: 14,
label: 'Europe',
children: [
{
value: 15,
label: 'France',
},
{
value: 19,
label: 'UK',
},
],
},
];
功能逻辑：
const tag = ref(-1); // 标识符（重要）
const change = (item: any) => {
// 逻辑代码
item.forEach((i: any) => {
if (i[0] != tag.value) {
tag.value = i[0];
}
}); // 如切换勾选，则让标识符的值等于勾选的父级的value
let filterd = item.filter((v: any) => v[0] == tag.value); // 过滤出与标识符相符的选项
casValue.value = [];
casValue.value.push(...filterd);
}
全部代码（demo）：
<template>
<div class="login">
<div class="content">
<el-cascader v-model="casValue" :props="props" :options="options" @change="change" />
</div>
</div>
</template>
<script lang="ts" setup>
import {
reactive, ref } from 'vue';
const options = [
{
value: 1,
label: 'Asia',
children: [
{
value: 2,
label: 'China',
},
{
value: 6,
label: 'Japan',
},
{
value: 10,
label: 'Korea',
},
],
},
{
value: 14,
label: 'Europe',
children: [
{
value: 15,
label: 'France',
},
{
value: 19,
label: 'UK',
},
],
},
];
const casValue: any = ref([]);
const tag = ref(-1); // 标识符（重要）
const props = reactive({
multiple: true,
});
const change = (item: any) => {
item.forEach((i: any) => {
if (i[0] != tag.value) {
tag.value = i[0];
}
}); // 如切换勾选，则让标识符的值等于勾选的父级的value
let filterd = item.filter((v: any) => v[0] == tag.value); // 过滤出与标识符相符的选项
casValue.value = [];
casValue.value.push(...filterd);
}
</script>
<style lang="scss" scoped>
.login {
position: absolute;
width: 100vw;
height: 100vh;
padding: 0 7.5% 0px 7.5%;
box-sizing: border-box;
background: white;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
background-image: url('../../assets/img/nbg2.jpeg');
background-size: cover;
background-position: center center;
background-repeat: no-repeat;
.content {
width: 356px;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
.body {
width: 100%;
padding: 20px;
border: 1px solid;
border-radius: 20px;
background: white;
}
}
input::-webkit-outer-spin-button,
input::-webkit-inner-spin-button {
-webkit-appearance: none;
}
input[type='number'] {
-moz-appearance: textfield;
appearance: textfield;
}
.title {
font-size: 24px;
// margin-top: 80px;
margin-bottom: 40px;
font-weight: 600;
}
.tel {
font-size: 16px;
font-weight: 500;
color: #b8bfcc;
display: block;
margin-bottom: 8px;
}
.container {
display: flex;
flex-direction: column;
.tel {
font-size: 16px;
font-weight: 500;
color: rgba(184, 191, 204, 1);
}
span {
font-size: 20px;
}
.el-input {
// width: 4px;
height: 60px;
margin-bottom: 20px;
::v-deep .el-input__inner {
font-size: 18px !important;
background: white;
}
}
}
.loginBtn {
margin: 0;
width: 100%;
height: 60px;
background: linear-gradient(129deg,
rgba(0, 170, 255, 1) 0%,
rgba(0, 127, 255, 1) 100%);
border-radius: 3px;
font-weight: 500;
color: rgba(255, 255, 255, 1);
outline: none;
border: none;
box-shadow: 0px 8px 20px 0px rgba(0, 170, 255, 0.1);
}
.btnContainer {
position: relative;
p {
width: 196px;
height: 35px;
background: linear-gradient(129deg, #00aaff 0%, #007fff 100%);
border-radius: 3px;
opacity: 0.49;
-webkit-filter: blur(6px);
filter: blur(6px);
position: absolute;
top: 28px;
left: 50%;
transform: translate(-50%, -50%);
}
}
.el-button {
display: flex;
position: relative;
font-size: 16px;
line-height: 60px;
padding: 0;
::v-depp span {
text-align: center;
margin: 0 auto;
}
}
}
</style>