实现思路：

1.点击当前行通过row拿到当前行数据。

2.将当前行数据传给子组件。

3.子组件监听父组件传过来的数据并映射在界面。

4.点击保存将修改的值传给父组件更新表格。

5.父组件收到修改过后的值，可以通过字段判断比如id，通过 findIndex找到是哪条数据修改了，然后在更新表格数据

table.vue

<template>
  <div>
    <el-button @click="add">新增数据</el-button>
    <el-table :data="tableData" border @cell-click="cellClick">
      <el-table-column prop="name" label="名称" width="180"></el-table-column>
      <el-table-column prop="age" label="年龄" width="180"></el-table-column>
      <el-table-column prop="gender" label="性别" width="180"></el-table-column>
      <el-table-column label="操作">
        <template #default="{ row }">
          <el-button type="primary" @click="edit(row)">编辑</el-button>
        </template>
      </el-table-column>
    </el-table>
    <Boundary
      v-if="showEdit"
      :update="person.selectedRow"
      @updateTable="updateTable"
    />
  </div>
</template>

<script setup>
import { ref, reactive } from "vue";

import Boundary from "./Boundary.vue";

const tableData = ref([
  { name: "张三", age: 18, gender: "男", id: 1 },
  { name: "李四", age: 20, gender: "女", id: 2 },
]);
const person = reactive({
  selectedRow: "",
});
const showEdit = ref(false);
// 点击单行
function cellClick(row) {
  showEdit.value = true;
  person.selectedRow = { ...row };
}
// 点击编辑按钮
function edit(row) {
  showEdit.value = true;
  person.selectedRow = { ...row };
}
// 点击按钮在表格中新增一条数据,id递增
function add() {
  tableData.value.push({
    name: "",
    age: null,
    gender: "",
    id: tableData.value.length + 1,
  });
}
// 根据id找出索引
function updateTable(newData) {
  const index = tableData.value.findIndex((item) => item.id === newData.id);
  tableData.value.splice(index, 1, newData);
}
</script>

Boundary.vue

<template>
  <div>
    <input v-model="person.inputData.name" placeholder="请输入名称" />
    <input v-model="person.inputData.age" placeholder="请输入年龄" />
    <input v-model="person.inputData.gender" placeholder="请输入性别" />
    <el-button type="primary" @click="save">保存</el-button>
  </div>
</template>

<script setup>
import { ref, reactive, watch } from "vue";
const emits = defineEmits(["updateTable"]);
let props = defineProps({
  update: {
    type: Object,
    default: {},
  },
});
const person = reactive({
  inputData: {
    name: "",
    age: "",
    gender: "",
    id: "",
  },
});
function save() {
  emits("updateTable", person.inputData);
}
// 接收表格传过来的数据
person.inputData = props.update;
// 监听父组件传过来的表格数据
watch(
  () => props.update,
  (val) => {
    person.inputData = val;
  },
  { deep: true }
);
</script>