经常碰到懒加载不回显的问题，使用起来很不方便，于是花了些时间二次开发了这个组件，希望对遇到相同问题的人有帮助。
el-cascader-plus基于 element-ui 级联二次封装，弥补了原 element-ui 级联组件懒加载经常无法回显的不足，用法与原级联组件一致。
使用前请确保安装了 vue 和 element ui （或者已单独按需引入 element ui 的级联 Cascader）
版本推荐 "vue": "^2.6.11","element-ui": "^2.15.13",
配置参数同 ElementUI 的 Cascader 级联选择器，可参考其文档ElementUI 官方文档
新增的属性
| 参数 | 说明 | 类型 | 可选值 | 默认值 | 是否必须 |
|---|---|---|---|---|---|
| maxLevel | 懒加载最大层级，最小值0 | Number | 整数 | 1000 | 否 |
优化点：
1、修复原组件懒加载单选数据加载延迟的情况下不响应数据变动、不触发回显的问题
2、修复原组件懒加载多选不响应数据变动、不触发回显的问题
3、单选懒加载做了回显速度优化，比原组件单选懒加载回显速度会快一些
4、新增一个prop属性：maxLevel,可限制懒加载最大层级，整数，最小值0,默认值1000
5、props中的lazyLoad在原基础上对resolve做了一点小修改。
props{
lazy:true,
lazyLoad:this.getNode
}
getNode(node, resolve) {
//根据node获取子集操作
resolve(params)
}
// 其中params可为普通数据和promise(要有resolve值)
npm i el-cascader-plus --save
在 main.js 中写入下面的代码就可以全局使用
import elCascaderPlus from "el-cascader-plus";
Vue.use(elCascaderPlus);在组件中单独使用
import elCascaderPlus from "el-cascader-plus";
export default {
name: "demo",
components: {
elCascaderPlus,
},
};<template>
<div class="demo">
<div class="mg20 title">el-cascader-plus</div>
<div class="mg20">
<div class="mg20">el-cascader-plus单选</div>
<el-cascader-plus
style="width: 400px"
ref="cascader"
v-model="value"
@change="change"
:options="options"
></el-cascader-plus>
</div>
<div class="mg20">
<div class="mg20">el-cascader-plus单选不关联</div>
<el-cascader-plus
style="width: 400px"
ref="cascader"
v-model="value1"
:props="{ checkStrictly: true }"
@change="change"
:options="options"
></el-cascader-plus>
</div>
<div class="mg20">
<div class="mg20">el-cascader-plus多选</div>
<el-cascader-plus
style="width: 400px"
ref="cascader"
v-model="multipleValue"
:props="{ multiple: true }"
@change="change"
:options="options"
></el-cascader-plus>
</div>
<div class="mg20">
<div class="mg20">el-cascader-plus多选不关联</div>
<el-cascader-plus
style="width: 400px"
ref="cascader"
v-model="multipleValue1"
:props="{ multiple: true, checkStrictly: true }"
@change="change"
:options="options"
></el-cascader-plus>
</div>
<div class="mg20">
<div class="mg20">el-cascader-plus懒加载单选</div>
<el-cascader-plus
style="width: 400px"
ref="cascader"
v-model="value"
:props="props"
@change="change"
></el-cascader-plus>
</div>
<div class="mg20">
<div class="mg20">el-cascader-plus懒加载单选不关联</div>
<el-cascader-plus
style="width: 400px"
ref="cascader"
v-model="value1"
:props="{ ...props, checkStrictly: true }"
@change="change"
></el-cascader-plus>
</div>
<div class="mg20">
<div class="mg20">el-cascader-plus懒加载多选</div>
<el-cascader-plus
style="width: 400px"
ref="cascader"
v-model="multipleValue"
:props="{ ...props, multiple: true }"
@change="change"
></el-cascader-plus>
</div>
<div class="mg20">
<div class="mg20">el-cascader-plus懒加载多选不关联</div>
<el-cascader-plus
style="width: 400px"
ref="cascader"
v-model="multipleValue1"
:props="{ ...props, multiple: true, checkStrictly: true }"
@change="change"
></el-cascader-plus>
</div>
<div class="mg20">
<div class="mg20">el-cascader-plus懒加载设置maxLevel为1</div>
<el-cascader-plus
:maxLevel="1"
style="width: 400px"
v-model="value2"
:props="props"
></el-cascader-plus>
</div>
</div>
</template>
<script>
import elCascaderPlus from "el-cascader-plus";
export default {
name: "demo",
components: {
elCascaderPlus,
},
data() {
return {
res: [],
// 级联懒加载
props: {
multiple: false,
lazy: true,
lazyLoad: this.getNode,
},
value: [17, 18, 19],
value1: [17, 18, 19],
value2: [],
multipleValue: [[17, 18, 19]],
multipleValue1: [[17, 18, 19]],
options: [
{
value: 1,
label: "东南",
children: [
{
value: 2,
label: "上海",
children: [
{
value: 3,
label: "普陀",
leaf: true,
},
{
value: 4,
label: "黄埔",
leaf: true,
},
{
value: 5,
label: "徐汇",
leaf: true,
},
],
},
{
value: 7,
label: "江苏",
children: [
{
value: 8,
label: "南京",
leaf: true,
},
{
value: 9,
label: "苏州",
leaf: true,
},
{
value: 10,
label: "无锡",
leaf: true,
},
],
},
{
value: 12,
label: "浙江",
children: [
{
value: 13,
label: "杭州",
leaf: true,
},
{
value: 14,
label: "宁波",
leaf: true,
},
{
value: 15,
label: "嘉兴",
leaf: true,
},
],
},
],
},
{
value: 17,
label: "西北",
children: [
{
value: 18,
label: "陕西",
children: [
{
value: 19,
label: "西安",
leaf: true,
},
{
value: 20,
label: "延安",
leaf: true,
},
],
},
{
value: 21,
label: "**维吾尔族自治区",
children: [
{
value: 22,
label: "乌鲁木齐",
leaf: true,
},
{
value: 23,
label: "克拉玛依",
leaf: true,
},
],
},
],
},
],
};
},
watch: {},
methods: {
change(e) {
console.log(e);
},
// 获取当前点击节点的子node,根据node数据和后端交互，此处为模拟后端请求
async getNode(node, resolve) {
const {
level, //层级
value,
data,
} = node;
// 模拟后端请求
// 0级处理
if (level == 0) {
let options = JSON.parse(JSON.stringify(this.options));
let nodes = options.map((v, index) => {
delete v.children;
return {
...v,
};
});
setTimeout(() => resolve(nodes), 500);
} else {
this.res = [];
let options = JSON.parse(JSON.stringify(this.options));
for (let i = 0; i < options.length; i++) {
this.findChildren(options[i], value);
}
// 去除子集的children
let nodes = [];
if (this.res.length) {
nodes = this.res.map((v, index) => {
delete v.children;
return {
...v,
};
});
}
setTimeout(() => resolve(nodes), 500);
}
},
// 找到某个树节点并返回子集
findChildren(item, cid, flag = false) {
if (item.value == cid) {
flag = true;
}
if (flag && item.children && item.children.length) {
this.res = [];
this.res = item.children;
}
if (!item.children) {
return;
} else {
item.children.forEach((child) => {
this.findChildren(child, cid, false);
});
}
},
},
};
</script>
<style>
.mg20 {
margin-top: 20px;
}
.title {
font-weight: bold;
font-size: 26px;
}
</style>