大致思路：
把所有选择的数据全部存到一个大数组中，切页的时候匹配原数据利用ref节点的.toggleRowSelection方法进行回显
具体步骤：
1、勾选和全选时需要判断是选中还是取消，然后更新大数组数据。
2、分页获取新数据之后匹配当前页应该选中的数据，使用 multipleTableRef.value!.toggleRowSelection(row, true);进行回显
所有代码：（示例为前端分页）
html
<template><div style="padding: 20px"><el-tableref="multipleTableRef":data="tableData"@select-all="selectAllChange"@select="handleSelectionChange"><el-table-column type="selection" width="55" /><el-table-column prop="username" label="用户名" show-overflow-tooltip /><el-table-column prop="firstName" label="姓名" show-overflow-tooltip /><el-table-column prop="email" label="邮箱" show-overflow-tooltip /></el-table><!-- 分页器 --><div class="pagination"><el-paginationv-model:current-page="pagination.pageNum"v-model:page-size="pagination.pageSize":page-sizes="[10, 20, 50, 100]"layout="total, prev, pager, next,sizes, jumper":total="pagination.total"@size-change="handleSizeChange"@current-change="handleCurrentChange"/></div><el-button type="primary" @click="yesTo">确 定</el-button></div>
</template>js
<script setup lang="ts">
import { ref, reactive, nextTick } from "vue";
import { ElMessage } from "element-plus";
import { setUsers } from "../../utils/api";let listAll: any = []; // 存起来选中的数据
let multipleSelection: any = []; // 当前页选中的数据
const multipleTableRef = ref(); // 表格reflet tableData = ref<any>([]); // 表格数据
let allList = reactive<any>([]);
//分页器
const pagination = reactive<any>({pageNum: 1,pageSize: 10,total: 0,
});// 前端分页-切割数据
const paging = () => {// 起始位置 = (当前页 - 1) x 每页的大小const start = (pagination.pageNum - 1) * pagination.pageSize;// 结束位置 = 当前页 x 每页的大小const end = pagination.pageNum * pagination.pageSize;tableData.value = allList.slice(start, end);
};// 获取列表数据
const getList = async () => {// 接口请求allList = [{id:1, username: "admin1", firstName: "管理员", email: "123456@163.com" },{id:2, username: "admin2", firstName: "管理员", email: "123456@163.com" },{id:3, username: "admin3", firstName: "管理员", email: "123456@163.com" },{id:4, username: "admin4", firstName: "管理员", email: "123456@163.com" },{id:5, username: "admin5", firstName: "管理员", email: "123456@163.com" },{id:6, username: "admin6", firstName: "管理员", email: "123456@163.com" },{id:7, username: "admin7", firstName: "管理员", email: "123456@163.com" },{id:8, username: "admin8", firstName: "管理员", email: "123456@163.com" },{id:9, username: "admin9", firstName: "管理员", email: "123456@163.com" },{id:10, username: "admin10", firstName: "管理员", email: "123456@163.com" },{id:11, username: "admin11", firstName: "管理员", email: "123456@163.com" },{id:12, username: "admin12", firstName: "管理员", email: "123456@163.com" },{id:13, username: "admin13", firstName: "管理员", email: "123456@163.com" },{id:14, username: "admin14", firstName: "管理员", email: "123456@163.com" },{id:15, username: "admin15", firstName: "管理员", email: "123456@163.com" },{id:16, username: "admin16", firstName: "管理员", email: "123456@163.com" },{id:17, username: "admin17", firstName: "管理员", email: "123456@163.com" },{id:18, username: "admin18", firstName: "管理员", email: "123456@163.com" },];pagination.total = allList.length;paging(); toggleSelection(getTurn()); // 回显勾选
};
getList();// 确认导入
const yesTo = async () => {if (listAll.length) {listAll = deduplicate(listAll, "username"); //去重await setUsers(listAll);ElMessage.success("导入成功");getList();} else {ElMessage.warning("请先选择用户！");}
};// 匹配获取当前页应该选中的数据
const getTurn = () => {let list: any = [];listAll.forEach((v: any) => {tableData.value.forEach((s: any) => {if (v.username == s.username) list.push(s);});});return list;
};
// 勾选时
const handleSelectionChange = (val: any, item: any) => {multipleSelection = val;listAll.push(...multipleSelection);if (val.includes(item)) {//勾选时做的事} else {//取消勾选时做的事，listAll.forEach((v: any, i: number) => {if (v.username == item.username) {listAll.splice(i, 1);}});}
};
// 全选
const selectAllChange = (val: any) => {if (val.length) {multipleSelection = JSON.parse(JSON.stringify(val));listAll.push(...val);} else {multipleSelection.forEach((v: any) => {listAll.forEach((s: any, i: number) => {if (v.username == s.username) {listAll.splice(i, 1);}});});multipleSelection = [];}
};
// 当前页之前勾选过的数据 - 回显
const toggleSelection = (rows?: any) => {nextTick(() => {if (rows) {rows.forEach((row: any) => {multipleTableRef.value!.toggleRowSelection(row, true);});} else {multipleTableRef.value!.clearSelection();}});
};// 分页事件
const handleSizeChange = (val: number) => {pagination.page = 1;pagination.limit = val;if (listAll.length) {listAll = deduplicate(listAll, "username"); //去重}getList();
};
const handleCurrentChange = (val: number) => {pagination.page = val;if (listAll.length) {listAll = deduplicate(listAll, "username"); //去重}getList();
};
// 数组去重方法
const deduplicate = (arr: any, t: any) => {const newArr = [arr[0]];for (let i = 1; i < arr.length; i++) {let repeat = false;for (let j = 0; j < newArr.length; j++) {if (t && arr[i][t] === newArr[j][t]) {repeat = true;break;}}if (!repeat) newArr.push(arr[i]);}return newArr;
};
</script>
