今天做到一个需求，前端下拉筛选出住户姓名，表单中自动带出手机号等信息。

1.首先，后端定义一个接口，用来返回查询的住户信息，注意请求url映射和请求方法和前端对应。

2.在前端js中定义发送的请求，与后端保持一致

3.前端页面导入js，定义下拉数据，创建下拉请求方法，并且在新增和修改的方法中调用，这样打开页面的时候就能拿到下拉数据。

4.添加下拉框，数据选择刚才在data中定义的tenantsOptions，已经通过新增或修改接口获取过数据，此时打开前端就可以拿到下拉数据。这里定义的 @change="roomSelectChange" 就是监听下拉变更实现输入框联动的关键。（注意一下此处绑定的值，我存id实际页面显示的是name，我把要存数据库的name隐藏了)

这里实际上是通过下拉选择的值，去遍历选项返回的数据，找到对应的一条租户信息，将拿到的租户信息与其他input属性做关联。（觉得遍历数据太多，也可以拿到下拉的值，单独写一个方法去请求后端，获取匹配的数据，然后与input做关联）

5.准备完成，打开页面来看看吧。

完美！下面贴上前端全部的代码,自己按照需求改动。

index.vue

<template>
    <div class="app-container">
        <el-form :model="queryParams" ref="queryForm" size="small" :inline="true" v-show="showSearch" label-width="68px">

            <el-form-item label="房间号" prop="roomNo">
                <el-input v-model="queryParams.roomNo" placeholder="请输入房间号" clearable @keyup.enter.native="handleQuery" />
            </el-form-item>
            <el-form-item label="住户姓名" prop="tenantsName">
                <el-input v-model="queryParams.tenantsName" placeholder="请输入住户姓名" clearable
                    @keyup.enter.native="handleQuery" />
            </el-form-item>
            <el-form-item label="手机号" prop="phone">
                <el-input v-model="queryParams.phone" placeholder="请输入手机号" clearable @keyup.enter.native="handleQuery" />
            </el-form-item>
            <el-form-item label="身份证号" prop="idCard">
                <el-input v-model="queryParams.idCard" placeholder="请输入身份证号" clearable @keyup.enter.native="handleQuery" />
            </el-form-item>
            <el-form-item label="入住时间" prop="checkInTime">
                <el-date-picker clearable v-model="queryParams.checkInTime" type="date" value-format="yyyy-MM-dd"
                    placeholder="请选择入住时间">
                </el-date-picker>
            </el-form-item>
            <el-form-item label="退宿时间" prop="checkOutTime">
                <el-date-picker clearable v-model="queryParams.checkOutTime" type="date" value-format="yyyy-MM-dd"
                    placeholder="请选择退宿时间">
                </el-date-picker>
            </el-form-item>
            <el-form-item label="是否持有钥匙" prop="keyHold">
                <el-select v-model="queryParams.keyHold" placeholder="请选择是否持有钥匙" clearable>
                    <el-option v-for="dict in dict.type.sys_yes_no" :key="dict.value" :label="dict.label"
                        :value="dict.value" />
                </el-select>
            </el-form-item>
            <el-form-item label="是否归还钥匙" prop="keyReturn">
                <el-select v-model="queryParams.keyReturn" placeholder="请选择是否归还钥匙" clearable>
                    <el-option v-for="dict in dict.type.sys_yes_no" :key="dict.value" :label="dict.label"
                        :value="dict.value" />
                </el-select>
            </el-form-item>
            <el-form-item>
                <el-button type="primary" icon="el-icon-search" size="mini" @click="handleQuery">搜索</el-button>
                <el-button icon="el-icon-refresh" size="mini" @click="resetQuery">重置</el-button>
            </el-form-item>
        </el-form>

        <el-row :gutter="10" class="mb8">
            <el-col :span="1.5">
                <el-button type="primary" plain icon="el-icon-plus" size="mini" @click="handleAdd"
                    v-hasPermi="['basedata:tenants:add']">新增
                </el-button>
            </el-col>
            <el-col :span="1.5">
                <el-button type="success" plain icon="el-icon-edit" size="mini" :disabled="single" @click="handleUpdate"
                    v-hasPermi="['basedata:tenants:edit']">修改
                </el-button>
            </el-col>
            <el-col :span="1.5">
                <el-button type="danger" plain icon="el-icon-delete" size="mini" :disabled="multiple" @click="handleDelete"
                    v-hasPermi="['basedata:tenants:remove']">删除
                </el-button>
            </el-col>
            <el-col :span="1.5">
                <el-button type="warning" plain icon="el-icon-download" size="mini" @click="handleExport"
                    v-hasPermi="['basedata:tenants:export']">导出
                </el-button>
            </el-col>
            <right-toolbar :showSearch.sync="showSearch" @queryTable="getList"></right-toolbar>
        </el-row>

        <el-table v-loading="loading" :data="roomtenantsList" @selection-change="handleSelectionChange">
            <el-table-column type="selection" width="55" align="center" />
            <el-table-column label="房间号" align="center" prop="roomNo" />
            <el-table-column label="住户姓名" align="center" prop="tenantsName" />
            <el-table-column label="手机号" align="center" prop="phone" />
            <el-table-column label="身份证号" align="center" prop="idCard" />
            <el-table-column label="入住时间" align="center" prop="checkInTime" width="180">
                <template slot-scope="scope">
                    <span>{{ parseTime(scope.row.checkInTime, '{y}-{m}-{d}') }}</span>
                </template>
            </el-table-column>
            <el-table-column label="退宿时间" align="center" prop="checkOutTime" width="180">
                <template slot-scope="scope">
                    <span>{{ parseTime(scope.row.checkOutTime, '{y}-{m}-{d}') }}</span>
                </template>
            </el-table-column>
            <el-table-column label="是否持有钥匙" align="center" prop="keyHold">
                <template slot-scope="scope">
                    <dict-tag :options="dict.type.sys_yes_no" :value="Number(scope.row.keyHold)" />
                </template>
            </el-table-column>
            <el-table-column label="是否归还钥匙" align="center" prop="keyReturn">
                <template slot-scope="scope">
                    <dict-tag :options="dict.type.sys_yes_no" :value="Number(scope.row.keyReturn)" />
                </template>
            </el-table-column>
            <el-table-column label="备注" align="center" prop="remark" />
            <el-table-column label="操作" align="center" class-name="small-padding fixed-width">
                <template slot-scope="scope">
                    <el-button size="mini" type="text" icon="el-icon-edit" @click="handleUpdate(scope.row)"
                        v-hasPermi="['basedata:tenants:edit']">修改
                    </el-button>
                    <el-button size="mini" type="text" icon="el-icon-delete" @click="handleDelete(scope.row)"
                        v-hasPermi="['basedata:tenants:remove']">删除
                    </el-button>
                </template>
            </el-table-column>
        </el-table>

        <pagination v-show="total > 0" :total="total" :page.sync="queryParams.pageNum" :limit.sync="queryParams.pageSize"
            @pagination="getList" />

        <!-- 添加或修改入住信息对话框 -->
        <el-dialog :title="title" :visible.sync="open" width="500px" append-to-body>
            <el-form ref="form" :model="form" :rules="rules" label-width="80px">

                <el-form-item label="房间号" prop="roomId">
                    <el-select v-model="form.roomId" placeholder="请选择房间号" @change="roomSelectChange">
                        <el-option v-for="item in roomOptions" :key="item.id" :label="item.roomNo"
                            :value="item.id"></el-option>
                    </el-select>
                </el-form-item>

                <el-form-item label="房间号" prop="roomNo" v-show="false">
                    <el-input v-model="form.roomNo" placeholder="请输入房间号" />
                </el-form-item>
                <el-form-item label="住户姓名" prop="tenantsId">
                    <el-select v-model="form.tenantsId" placeholder="请选择住户姓名" @change="tenantsSelectChange">
                        <el-option v-for="item in tenantsOptions" :key="item.id" :label="item.tenantsName"
                            :value="item.id"></el-option>
                    </el-select>
                </el-form-item>
                <el-form-item label="住户姓名" prop="tenantsName" v-show="false">
                    <el-input v-model="form.tenantsName" placeholder="请输入住户姓名" />
                </el-form-item>
                <el-form-item label="手机号" prop="phone">
                    <el-input v-model="form.phone" placeholder="请输入手机号" />
                </el-form-item>
                <el-form-item label="身份证号" prop="idCard">
                    <el-input v-model="form.idCard" placeholder="请输入身份证号" />
                </el-form-item>
                <el-form-item label="入住时间" prop="checkInTime">
                    <el-date-picker clearable v-model="form.checkInTime" type="date" value-format="yyyy-MM-dd"
                        placeholder="请选择入住时间">
                    </el-date-picker>
                </el-form-item>
                <el-form-item label="退宿时间" prop="checkOutTime">
                    <el-date-picker clearable v-model="form.checkOutTime" type="date" value-format="yyyy-MM-dd"
                        placeholder="请选择退宿时间">
                    </el-date-picker>
                </el-form-item>
                <el-form-item label="是否持有钥匙" prop="keyHold">
                    <el-select v-model="form.keyHold" placeholder="请选择是否持有钥匙" clearable>
                        <el-option v-for="dict in dict.type.sys_yes_no" :key="dict.value" :label="dict.label"
                            :value="String(dict.value)" />
                    </el-select>
                </el-form-item>
                <el-form-item label="是否归还钥匙" prop="keyReturn">
                    <el-select v-model="form.keyReturn" placeholder="请选择是否归还钥匙" clearable>
                        <el-option v-for="dict in dict.type.sys_yes_no" :key="dict.value" :label="dict.label"
                            :value="String(dict.value)" />
                    </el-select>
                </el-form-item>
                <el-form-item label="备注" prop="remark">
                    <el-input v-model="form.remark" type="textarea" placeholder="请输入内容" />
                </el-form-item>
            </el-form>
            <div slot="footer" class="dialog-footer">
                <el-button type="primary" @click="submitForm">确 定</el-button>
                <el-button @click="cancel">取 消</el-button>
            </div>
        </el-dialog>
    </div>
</template>

<script>
import { getRoomTenants, listRoomTenants, updateRoomTenants, addRoomTenants, delRoomTenants } from "@/api/base/roomtenants";
import { roomoptionselect, tenantsoptionselect } from "@/api/base/common";

export default {
    name: "RoomTenants",
    dicts: ['sys_yes_no'],
    data() {
        return {
            //房间下拉框数据
            roomOptions: [],
            //住户下拉框数据
            tenantsOptions: [],
            // 遮罩层
            loading: true,
            // 选中数组
            ids: [],
            // 非单个禁用
            single: true,
            // 非多个禁用
            multiple: true,
            // 显示搜索条件
            showSearch: true,
            // 总条数
            total: 0,
            // 入住信息表格数据
            roomtenantsList: [],
            // 弹出层标题
            title: "",
            // 是否显示弹出层
            open: false,
            // 查询参数
            queryParams: {
                pageNum: 1,
                pageSize: 10,
                roomId: null,
                roomNo: null,
                tenantsId: null,
                tenantsName: null,
                phone: null,
                idCard: null,
                checkInTime: null,
                checkOutTime: null,
                keyHold: null,
                keyReturn: null,
            },
            // 表单参数
            form: {},
            // 表单校验
            rules: {
            }
        };
    },
    created() {
        this.getList();
    },
    methods: {

        /**查询宿舍列表*/
        getRoomList() {
            roomoptionselect().then(response => {
                this.roomOptions = response.data;
            })
        },

        /**查询宿舍列表*/
        getTenantsList() {
            tenantsoptionselect().then(response => {
                this.tenantsOptions = response.data;
            })
        },
        /** 查询入住信息列表 */
        getList() {
            this.loading = true;
            listRoomTenants(this.queryParams).then(response => {
                this.roomtenantsList = response.data.rows;
                this.total = response.data.total;
                this.loading = false;
            });
        },
        // 取消按钮
        cancel() {
            this.open = false;
            this.reset();
        },
        // 表单重置
        reset() {
            this.form = {
                id: null,
                roomId: null,
                roomNo: null,
                tenantsId: null,
                tenantsName: null,
                phone: null,
                idCard: null,
                checkInTime: null,
                checkOutTime: null,
                keyHold: null,
                keyReturn: null,
                remark: null,
                createBy: null,
                createTime: null,
                updateBy: null,
                updateTime: null,
            };
            this.resetForm("form");
        },
        /** 搜索按钮操作 */
        handleQuery() {
            this.queryParams.pageNum = 1;
            this.getList();
        },
        /** 重置按钮操作 */
        resetQuery() {
            this.resetForm("queryForm");
            this.handleQuery();
        },
        // 多选框选中数据
        handleSelectionChange(selection) {
            this.ids = selection.map(item => item.id)
            this.single = selection.length !== 1
            this.multiple = !selection.length
        },
        /** 新增按钮操作 */
        handleAdd() {
            this.reset();
            this.open = true;
            this.title = "添加入住信息";
            this.getRoomList();
            this.getTenantsList();
        },
        /** 修改按钮操作 */
        handleUpdate(row) {
            this.reset();
            const id = row.id || this.ids;
            this.getRoomList();
            this.getTenantsList();
            getRoomTenants(id).then(response => {
                this.form = response.data;
                this.open = true;
                this.title = "修改入住信息";
            });
        },
        /** 提交按钮 */
        submitForm() {
            this.$refs["form"].validate(valid => {
                if (valid) {
                    if (this.form.id != null) {
                        updateRoomTenants(this.form).then(response => {
                            this.$modal.msgSuccess("修改成功");
                            this.open = false;
                            this.getList();
                        });
                    } else {
                        addRoomTenants(this.form).then(response => {
                            this.$modal.msgSuccess("新增成功");
                            this.open = false;
                            this.getList();
                        });
                    }
                }
            });
        },
        /** 删除按钮操作 */
        handleDelete(row) {
            const ids = row.id || this.ids;
            this.$modal.confirm('是否确认删除入住信息id为"' + ids + '"的数据项？').then(function () {
                return delRoomTenants(ids);
            }).then(() => {
                this.getList();
                this.$modal.msgSuccess("删除成功");
            }).catch(() => { });
        },
        /** 导出按钮操作 */
        handleExport() {
            this.download('basedata/roomtenants/export', {
                ...this.queryParams
            }, `tenants_${new Date().getTime()}.xlsx`)
        },
        /** 宿舍下拉联动 */

        roomSelectChange() {
            console.log("-------2222----------", this.roomOptions);
            const item = this.roomOptions.find(item => item.id === this.form.roomId);
            this.form.roomNo = item.roomNo;
        },
        /** 租户下拉联动 */
        tenantsSelectChange() {
            const item = this.tenantsOptions.find(item => item.id === this.form.tenantsId);
            this.form.tenantsName = item.tenantsName;
            this.form.phone = item.phone;
            this.form.idCard = item.idCard;

        },

    },


};



</script>

common.js

import request from '@/utils/request'
import Cookies from 'js-cookie'

/**
 * 参数业务特殊处理
 * @param {*} params
 * @returns
 */
export function handleParams(params) {
  if (!params) params = {}
  params = Object.assign(params)
  return params
}

// get 请求
export function httpGet(url, params) {
  return request({
    url: url,
    method: 'get',
    params: handleParams(params)
  })
}
// post 请求
export function httpPost(url, params) {
  return request({
    url: url,
    method: 'post',
    data: handleParams(params)
  })
}
// put 请求
export function httpPut(url, params) {
  return request({
    url: url,
    method: 'put',
    data: params
  })
}
// delete 请求
export function httpDelete(url) {
  return request({
    url: url,
    method: 'delete'
  })
}

// url 拼接
// url格式如：/system/{taskid}/{id}
// data 格式如 {taskid: 1, id: 2}
export function httpUrlJoint (url, data) {
  for (let i in data) {
    url = url.replace(`{${i}}`, data[i])
  }
  return url
}

export function formHttpPost(url,params) {
  return request({
    url: url,
    method: 'post',
    data: params,
    headers: {
      'Content-Type': 'application/x-www-form-urlencoded'
    }
  })
}

//获取宿舍选择框列表
export function roomoptionselect() {
  return request({
    url: '/dm/room/optionselect',
    method: 'get'
  })
}

//获取人员选择框列表
export function tenantsoptionselect() {
  return request({
    url: '/dm/tenants/optionselect',
    method: 'get'
  })
}