elementui中树形表格切换展开不同层级的示例代码

<template>
    <div class="myDiv">
        <el-row style="margin:10px 0">
            <el-col :span="22">
                <el-button type="primary" size="mini" plain @click="expandLevel(0)">展开一级</el-button>
                <el-button type="primary" size="mini" plain @click="expandLevel(1)">展开二级</el-button>
                <el-button type="primary" size="mini" plain @click="expandLevel(2)">展开三级</el-button>
                <el-button type="primary" size="mini" plain @click="expandLevel(3)">展开四级</el-button>
            </el-col>
        </el-row>
        //下面写法主要方便大家作为组件封装使用
        <el-table :data="tableData" style="width: 100%" row-key="id" :expand-row-keys="expandId" border :tree-props="{children: 'children', hasChildren: 'hasChildren'}">
            <el-table-column show-overflow-tooltip :prop="item.prop" :width="item.width" :label="item.label" v-for="(item,i) in treeProps" :key="i">
                <template slot-scope="scope">
                    <!-- 自定义数据-展示slot插槽 -->
                    <slot v-if="item.slot" :name="item.prop" :scope="scope">-</slot>
                    <!-- 非自定义处理(判空) -->
                    <span v-else-if="scope.row[item.prop] === '' || scope.row[item.prop] === null">-</span>
                    <!-- 非自定义处理(展示数组数据)-换行展示 -->
                    <div v-else-if="Array.isArray( scope.row[item.prop])==true">
                        <div v-for="aa in scope.row[item.prop]" ::key="aa">
                            {{aa}}
                        </div>
                    </div>
                    <!-- 非自定义处理(正常展示) -->
                    <span v-else>{{scope.row[item.prop]}}</span>
                </template>
            </el-table-column>
        </el-table>
 
    </div>
</template>
 
<script>
export default {
    name: '',
    components: {},
    props: {},
    data() {
        return {
            expandNum: 0, //展开层级的数字
            expandId: [],
            treeProps: [{ prop: 'date', label: '评估项目', width: '400' },
            { prop: 'address', label: '指标属性', width: '300' },
            { prop: 'map', label: '采集要点', width: '300' }],
            tableData: [{
                id: 1,
                date: '快速反应能力',
                name: '-',
                address: '-',
                level: 1,
                children: [{
                    id: 11,
                    date: '快速筹划',
                    name: '-',
                    address: '-',
                    level: 2,
                    children: [{
                        id: 111,
                        date: '方案计划齐全',
                        name: '-',
                        address: '-',
                        level: 3,
                        children: [{
                            id: 1111,
                            date: '四级111',
                            name: '四级111',
                            address: '定量',
                            map: ['11', '22', '33'],
                            level: 4,
                        }, {
                            id: 1112,
                            date: '四级1',
                            name: '四级2',
                            address: '定量',
                            map: ['11', '22', '33'],
                            level: 4,
                        }, {
                            id: 1113,
                            date: '四级1',
                            name: '四级3',
                            address: '定量',
                            map: ['11', '22', '33'],
                            level: 4,
                        }, {
                            id: 1114,
                            date: '四级1',
                            name: '四级4',
                            address: '定量',
                            level: 4,
                        }]
                    }]
                }]
            }, {
                id: 2,
                date: '突发事件处理能力',
                name: '-',
                address: '-',
                level: 1,
                children: [{
                    id: 21,
                    date: '随机应变',
                    name: '-',
                    address: '-',
                    level: 2,
                    children: [{
                        id: 211,
                        date: '方案计划齐全',
                        name: '-',
                        address: '-',
                        level: 3,
                        children: [{
                            id: 2111,
                            date: '四级1',
                            name: '四级1',
                            level: 4,
                            address: '定量'
                        }]
                    }]
                }]
            }],
            expandNumCopy: 0,//保留当前展开的层级
        }
    },
    created() {
    },
    methods: {
        /** 展开层级 */
        expandLevel(i) {
            this.expandNum = i
            this.expandId.splice(0);
            if (this.expandNum > 0) { //expandNum==0 为第一层级 不需要展开 大于0再执行
                this.setExpandKeys(this.tableData1, i)
            }
        },
        /** 递归设置展开层级对应的id数组 */
        setExpandKeys(dataList, num) {
            --num;
            if (num >= 0) {
                for (var i = 0; i < dataList.length; i++) {
                    this.expandId.push(`${dataList[i].id}`);
                    if (dataList[i].children) {
                        this.setExpandKeys(dataList[i].children, num);
                    }
                }
            }
        },
 
    },
    mounted() { }
}
</script>
<style lang="scss" scoped>
</style>