根据最新的工作需求中指示，要求Tree树组件为lazy懒加载，且能够进行复选框选择，这个实现简单，设置show-checkbox即可，若此处要求叶子节点也不能包含复选框，就有些困扰了
1.首先按照官网
拷贝tree树组件代码，设置完show-checkbox，图中查看更多为叶子节点，且设置数据节点属性为disabled
<el-tree
ref="treeRef"
class="treeDom"
lazy
show-checkbox
:props="defaultProps"
highlight-current="true"
:load="lazyLoadMore"
:expand-on-click-node="false"
:default-expanded-keys="defaultExpandKeys"
:default-checked-keys="defaultCheckedKeys"
node-key="id"
@node-expand="handleNodeExpand"
@node-collapse="handleNodeCollapse"
@node-click="handleNodeClick"
@check="handleCheck"
>
<div slot-scope="{ node, data }" class="custom-tree-node">
<!-- 查看更多 -->
<span
v-if="data.id ==='loadmore'"
class="tree-node loadmore"
@click="loadMoreNode(node,data)"
>
<el-link>{{ node.label }}</el-link>
</span>
<!-- 数据到底了 -->
<span
v-if="data.id ==='disabledload'"
class="tree-node no-data"
style="color: #999; cursor: auto;"
>
{{ node.label }}
</span>
<!-- 普通节点 -->
<el-tooltip
class="item"
effect="light"
placement="right-start"
>
<div slot="content" style="max-width: 300px;">
{{ node.label }}
</div>
<span v-if="data.id !=='loadmore' && data.id!=='disabledload'" class="span-tree-node" @click="loadMoreNode(node,data)">{{ node.label }}</span>
</el-tooltip>
</div>
</el-tree>
css样式如下：
::v-deep .span-tree-node {
width: 120px;
position: absolute;
text-overflow: ellipsis;
overflow: hidden;
color: #696969;
top: 50%;
transform: translateY(-50%);
}
::v-deep .treeDom {
width: 100%;
overflow-x: auto;
.custom-tree-node {
width: 100% !important;
position: relative;
}
2.由于属性是isleaf
所以lazy状态下叶子节点不会有加载目录符号，但此时，有个禁用复选框，现在只需要对它设置样式即可
::v-deep .el-tree .el-tree-node:last-child {
.el-tree-node__content .is-leaf +.el-checkbox.is-disabled{
display: none;
}
.el-tree-node__content.is-not-clickable{
cursor: pointer;
}
}
3. 分页懒加载实现功能也比较简单
可以复写tree树自带的load方法，load方法内携带两个返回参数，一个是node，一个是resolve，即懒加载数据必须是通过resolve就是return 将数据带回
async lazyLoadMore(node, resolve, parentNode = []) {
let id = node?.data?.id, pre = node?.data?.name, data = [], arrId = '';
if (node.level === 0) {
id = this.paramNode.parent;
return resolve([{id: id, name: id, leaf: false}]);
}
if (node.level === 1) {
pre = '';
}
// 节点各自的resolve
this.funcResolve.push({id: id, resolve: resolve});
this.funcResolve = this.funcResolve.filter((item, index, self)=>{
return self.findIndex(x=>x.id === item.id) === index;
});
// 判断获取分页查询的pre参数
if (id && id.indexOf('/') > -1) {
let arrIndex = id.lastIndexOf('/') + 1;
arrId = id.substring(arrIndex);
if (arrId === pre) pre = '';
}
// lazy加载查询接口
const { data: {items} } = await getInterfaceTreeDictory({parent: id || '', pre: pre || ''});
data = items.map(({interface_url: name, full_interface_url: id}) => {
return {name, id};
});
// 翻页信息添加
if (data.length >= this.pageSize) {
let nearName = data[data.length - 1].name;
data.push({name: '查看更多', id: 'loadmore', nearName: nearName, leaf: true, disabled: true});
}
// 查看更多加载需根据各自的resolve加载数组数据
if (parentNode && parentNode.length > 0) {
parentNode.push(...data);
return resolve(parentNode);
} else {
return resolve(data);
}
},
// 查看更多事件点击
loadMoreNode(node, data) {
if (data.id === 'loadmore') {
let nodeParentKey = node.parent.key ? node.parent.key : this.paramNode.parent;
let childNode = {
data: {
id: nodeParentKey,
name: data.nearName
}
}, resolve = '';
let parentNode = node.parent.childNodes.map(({key: id, label: name})=>{
return { name, id };
});
console.log(parentNode);
// 剔除自定义查看更多option数据
if (parentNode.length > 0) {
parentNode = parentNode.slice(0, -1);
}
// 选取resolve返回
if (parentNode.length <= this.pageSize) {
resolve = this.funcResolve.filter((item)=>{
return item.id === nodeParentKey;
});
// 调用原生Tree load方法
this.$refs.treeRef.load(childNode, resolve[0].resolve, parentNode);
}
}
},
代码内有一点需要注意，即每次查询接口的时候，和后台约定的规则是：不包含分页，需要传值两个参数，一个是parent，即当前节点的上一级所有层级拼接，另一个是pre即当前节点的子集，若第一次加载，pre可为空，若查看更多再一次加载pre为上一次加载数据data的最后一个元素id，作为传参；
eg：
- a、此时需要点击加载js，即 GET请求下param参数如下parent=172.24.114.143:8080/js&pre=
- b、此时继续点击查看更多，则传入parent=172.24.114.143:8080/js&pre=jquery-showloading
到此代码和效果都正常了~
以上为个人经验，希望能给大家一个参考，也希望大家多多支持编程网。
