须知

这是 vue2 版本，不过理论上 vue3 也能参考使用

可以直接打开 codepen 查看代码

效果图

代码

打不开 codepen 或者codepen 失效，查看下面代码参考

<script src="//unpkg.com/vue@2/dist/vue.js"></script>
<script src="//unpkg.com/element-ui@2.15.14/lib/index.js"></script>
<div id="app"><template><div><el-button @click="logMergedRowCount">Log</el-button><el-table row-key="id" @expand-change="expandChange" :data="tableData" :span-method="objectSpanMethod" border :tree-props="{children: 'children', hasChildren: 'hasChildren'}" style="width: 100%; margin-top: 20px"><el-table-column prop="name" label="姓名"></el-table-column><el-table-column prop="id" label="ID" width="180"></el-table-column><el-table-column prop="amount1" label="数值 1（元）"></el-table-column><el-table-column prop="amount2" label="数值 2（元）"></el-table-column><el-table-column prop="amount3" label="数值 3（元）"></el-table-column></el-table></div></template>
</div>

@import url("//unpkg.com/element-ui@2.15.14/lib/theme-chalk/index.css");

var Main = {data() {return {tableData: [],spanMap: {}, // 每层的 id => {子级有几个， 祖宗是谁}expandRowKeys: {}};},computed: {parentMap() {const keys = Object.entries(this.expandRowKeys).filter(([k, v]) => v).map(([k]) => k);console.log("keys", keys);let result = {};for (const item of keys) {const expandRow = this.spanMap[item];if (result[expandRow.parentId]) {result[expandRow.parentId] += expandRow.childCount;} else {result[expandRow.parentId] = expandRow.childCount;}}return result;}},mounted() {let datalist = [{id: "1",name: "一级事件",amount1: "165",amount2: "4.43",amount3: 12,children: [{id: "2",name: "二级事件1",amount1: "165",amount2: "4.43",amount3: 12,children: [{id: "3",name: "三级事件1",amount1: "165",amount2: "4.43",amount3: 12},{id: "4",name: "三级事件2",amount1: "165",amount2: "4.43",amount3: 12}]},{id: "5",name: "二级事件2",amount1: "165",amount2: "4.43",amount3: 12}]},{id: "6",name: "一级事件2",amount1: "165",amount2: "4.43",amount3: 12},{id: "7",name: "二级事件1",amount1: "165",amount2: "4.43",amount3: 12,children: [{id: "8",name: "三级事件1",amount1: "165",amount2: "4.43",amount3: 12},{id: "9",name: "三级事件2",amount1: "165",amount2: "4.43",amount3: 12}]},{id: "10",name: "三级事件1",amount1: "165",amount2: "4.43",amount3: 12},{id: "11",name: "三级事件2",amount1: "165",amount2: "4.43",amount3: 12}];datalist = this.preprocessData(datalist);this.tableData = datalist;},methods: {/*** 处理行展开状态变化的事件。* @param {Object} row - 当前行的数据对象。* @param {boolean} expanded - 表示行是否被展开。*/expandChange(row, expanded) {// 使用 Vue 的 $set 方法更新展开行的键值对，确保响应性this.$set(this.expandRowKeys, row.id, expanded);},/*** 打印合并行数的日志。*/logMergedRowCount() {// 打印合并行数的映射，用于调试或检查合并状态console.log(this.mergedRowCount);},preprocessData(data, id = "") {return data.map((item) => {const newItem = { ...item };newItem.parentId = id; // 将当前路径作为 parentId 属性if (this.spanMap[item.id]) {this.spanMap[item.id].childCount = item.children?.length || 0;} else {this.spanMap[item.id] = {childCount: item.children?.length || 0,parentId: id || item.id};}if (item.children && item.children.length > 0) {newItem.children = this.preprocessData(item.children, id || item.id);}return newItem;});},//进行表格合并objectSpanMethod({ row, column, rowIndex, columnIndex }) {if (columnIndex === 1) {if (row.parentId) {return {rowspan: 0,colspan: 0};} else {console.log("row.id", this.parentMap[row.id]);return {rowspan: (this.parentMap[row.id] ?? 0) + 1,colspan: 1};}}}}
};
var Ctor = Vue.extend(Main);
new Ctor().$mount("#app");