"vue": "^2.7.16",
"element-ui": "^2.15.14",

问题描述：

场景：首先我们是通过接口获取到数据之后 然后将返回的数据回显到表格上面

问题：直接将后端返回的数据循环的通过toggleRowSelection进行回显，发现无法选中！

问题出现的原因

通过 element 源码发现，table 在回显的时候必须使用表格里面的对象（实际是引用的地址），但实际上后端返回的数据对象是另一个对象地址 两者不是一样的 所以无法回显

源码地址：https://github.com/ElemeFE/element/blob/v2.15.14/packages/table/src/util.js

export function toggleRowStatus(statusArr, row, newVal) {let changed = false;const index = statusArr.indexOf(row);const included = index !== -1;const addRow = () => {statusArr.push(row);changed = true;};const removeRow = () => {statusArr.splice(index, 1);changed = true;};if (typeof newVal === 'boolean') {if (newVal && !included) {addRow();} else if (!newVal && included) {removeRow();}} else {if (included) {removeRow();} else {addRow();}}return changed;
}

在做对比的时候使用了 const index = statusArr.indexOf(row)。
因为table的数据是来自列表接口返回的list，而选中的模版是从详情接口里面获取的，对象的引用改变了。
所以 statusArr.indexOf(row) 找不到对象，toggleRowSelection 不会生效。

所以想要生效，只能将详情的数据取找 table 的数据 将找到的 table 数据通过toggleRowSelection进行回显。

全部代码：

<template><div><el-tableref="multipleTable":data="tableData"tooltip-effect="dark"style="width: 100%"row-key="id"@select="handleSingleSelect"><el-table-columntype="selection"width="55"reserve-selection></el-table-column><el-table-column label="日期" width="120"><template slot-scope="scope">{{ scope.row.date }}</template></el-table-column><el-table-column prop="id" label="id" width="120"></el-table-column><el-table-column prop="name" label="姓名" width="120"></el-table-column><el-table-columnprop="address"label="地址"show-overflow-tooltip></el-table-column></el-table><div style="margin-top: 20px"><span>需要回显的数据</span><br><div v-for="(item, index) in beforeSelect" :key="index">{{ item }}</div></div><div style="margin-top: 20px"><el-button @click="clearAllSelection()">清除所有选中</el-button><el-button @click="correctDisplayBeforeSelection()">回显之前选中的数据(正确的方式)</el-button><el-button @click="errorDisplayBeforeSelection()">回显之前选中的数据(错误的方式)</el-button><br>------------<br><el-button @click="getResponseSelectionData()">模拟后端返回的数据</el-button><el-button @click="correctResponseDisplayBeforeSelection()">回显后端返回的的数据(正确的方式)</el-button><el-button @click="errorResponseDisplayBeforeSelection()">回显后端返回的的数据(错误的方式)</el-button><br><br><el-button @click="clearBeforeSelection()">清空需要回显的数据</el-button></div></div>
</template><script>
export default {data() {return {tableData: [{date: '2016-05-03',name: '王小虎',address: '上海市普陀区金沙江路 1518 弄',id: 0,},{date: '2016-05-02',name: '王小虎',address: '上海市普陀区金沙江路 1518 弄',id: 1,},{date: '2016-05-04',name: '王小虎',address: '上海市普陀区金沙江路 1518 弄',id: 2,},{date: '2016-05-01',name: '王小虎',address: '上海市普陀区金沙江路 1518 弄',id: 3,},{date: '2016-05-08',name: '王小虎',address: '上海市普陀区金沙江路 1518 弄',id: 4,},{date: '2016-05-06',name: '王小虎',address: '上海市普陀区金沙江路 1518 弄',id: 5,},{date: '2016-05-07',name: '王小虎',address: '上海市普陀区金沙江路 1518 弄',id: 6,},],multipleSelection: [],beforeSelect: [],};},methods: {clearAllSelection() {this.$refs.multipleTable.clearSelection();},correctDisplayBeforeSelection() {this.beforeSelect.forEach((s) => {this.$refs.multipleTable.toggleRowSelection(s, true);});},errorDisplayBeforeSelection() {const copyData = JSON.parse(JSON.stringify(this.beforeSelect))copyData.forEach((s) => {this.$refs.multipleTable.toggleRowSelection(s, true);});},getResponseSelectionData() {const responseData = [{// date: '2016-05-06',// name: '王小虎',// address: '上海市普陀区金沙江路 1518 弄',id: 5,},{// date: '2016-05-07',// name: '王小虎',// address: '上海市普陀区金沙江路 1518 弄',id: 6,},];this.beforeSelect = responseData},handleSingleSelect(selection) {console.log('selection', selection);this.beforeSelect = selection;},clearBeforeSelection() {this.beforeSelect = []},errorResponseDisplayBeforeSelection() {this.beforeSelect.forEach((s) => {this.$refs.multipleTable.toggleRowSelection(s, true);});},correctResponseDisplayBeforeSelection() {this.tableData.forEach(s => {this.beforeSelect.forEach(v => {if (s.id === v.id) {this.$refs.multipleTable.toggleRowSelection(s, true);}})})}},
};
</script>