Angular 2 + 折腾记 ：(7) 初步了解表单：模板驱动及数据驱动及脱坑要点

前言

表单在整个系统中的作用相当重要，这里主要扯下响应表单的实现方式。

首先须要操作表单的模块引入这两个模块。

import { FormsModule, ReactiveFormsModule } from '@angular/forms';

---

表单控件响应的几种状态

模板驱动表单依赖FormsModule,数据驱动的表单依赖FormsModule,ReactiveFormsModule

一般做表单校验及操作推荐用数据驱动的方式，好维护和理解。。

---

模板驱动

模板驱动：主要是依赖[(ngModel)]和#scope_var以及原生表单控件属性(require,minlenght,maxlength等)来操作表单的那的值亦或者校验

• 一个最简单的样例

<!--#UserName 是局部变量，若是有ngmodel,拿到的就是一个响应对象。若是非ngmodel绑定的，则是dom元素代码-->
<!--testform这个局部变量保存了表单的全部相关信息-->
<!--ngSubmit是用来触发表单提交的-->
<!--ngModel相应变量的值-->
<!--$event是原生dom对象-->
<form  #testform="ngForm"  (ngSubmit)="Submit(testform.value,testform.valid)">
<label for="username">Name</label>
<input type="text" id="username" #UserName="username" class="form-control"
    required minlength="4" maxlength="24"
    name="username" [(ngModel)]="username" [ngModelChange]="validate($event)">
<div *ngIf="UserName.valid || (UserName.pristine && !testform.submitted)">
 您输入的值有误，请又一次输入
</div>
<button type="submit" >提交</button>
</form>

有两种方式处理来对上面的表单做校验；

1. 在Submit()函数内，在点击提交的时候对整个表单一一去推断，传统方式基本这样
2. 每一个控件输入的时候相应去触发相应的事件做校验,比方[ngModelChange]来处理双向绑定的值校验

---

数据驱动(Reactive Form)

响应式表表单：原理是一開始就构建整个表单，表单的值通过特殊指令formControlName一一关联(相似ngModel);

相关名词：

- FormGroup: 用来追踪表单控件有效状态及值 =》 能够理解为获取且能够操作整个表单的数据

- FormBuilder:表单数据构建工具[构建初始表单]，简化构建代码(包含了new FormGroup(),new FormControl(),new FormArray()),FormGroup()内置多种校验方式

- formControlName: 同步与FormGroup构建表单内同样字段的值！

项目中的案例

• html

<div [@flyIn]="true">
  <div class="beautify-form" *ngIf="!showLoading">
    <div class="page-header">
      欢迎登录
    </div>
    <form [formGroup]="form" (ngSubmit)="onSubmit(form)">
      <div class="form-group" [ngClass]="{ 'has-danger': form.controls.UserName.invalid && form.controls.UserName.value ,'has-success':  form.controls.UserName.valid && form.controls.UserName.value }">
        <div class="input-group input-group-lg">
          <span class="input-group-addon fpd fpd-ordinarylogin1"></span>
          <input type="text" class="form-control" formControlName="UserName" placeholder="手机号码 \ 邮箱 ">
        </div>
        <div class="form-control-feedback" *ngIf="(form.controls.UserName.dirty || form.controls.UserName.pristine) && form.controls.UserName.invalid && form.controls.UserName.value">账号不符合规范</div>
        <div class="form-control-feedback" *ngIf="(form.controls.UserName.dirty || form.controls.UserName.pristine) && form.controls.UserName.valid && form.controls.UserName.value">账号符合规范</div>
      </div>
      <div class="form-group" [ngClass]="{ 'has-danger': form.controls.PassWord.invalid && form.controls.PassWord.value ,'has-success': form.controls.PassWord.valid && form.controls.PassWord.value }">
        <div class="input-group input-group-lg">
          <span class="input-group-addon fpd fpd-mima"></span>
          <input type="PassWord" class="form-control" formControlName="PassWord" placeholder="请输入password">
        </div>
        <div class="form-control-feedback" *ngIf="(form.controls.PassWord.dirty || form.controls.PassWord.pristine) && form.controls.PassWord.invalid && form.controls.PassWord.value ">password不符合规范,请又一次输入</div>
        <div class="form-control-feedback" *ngIf="(form.controls.PassWord.dirty || form.controls.PassWord.pristine) && form.controls.PassWord.valid && form.controls.PassWord.value ">password符合规范</div>
      </div>
      <div class="form-group ">
        <div class="flex">
          <div class="beautify-wrap flex-wrap">
            <input type="checkbox" class="beautify-checkbox" name="rememberme" id="rememberAccount" formControlName="rememberAccount">
            <label for="rememberAccount"></label>记住账号
          </div>
          <!--<a [routerLink]="['/account/reset-pw']">忘记password</a>-->
        </div>
      </div>
      <div class="message-tips" *ngIf="messageTips">
        <i class="fpd fpd-error"></i> {{messageTips}}
      </div>
      <div class="form-group ">
        <button class="btn btn-lg btn-outline-success btn-block" type="submit" [disabled]="form.invalid">登录</button>
      </div>
      <div class="form-group">
        <span class="noaccount-notify">没有账号？点击</span><a [routerLink]="['/account/collect']" class="collect-user">用户登记</a>
      </div>
    </form>
  </div>
  <div class="loading" *ngIf="showLoading">
    <app-mit-loading [option]="'load4'"></app-mit-loading>
  </div>
</div>

• component.ts

import { Component, OnInit, OnDestroy } from '@angular/core';
import { FormGroup, Validators, FormBuilder } from '@angular/forms'; // 引入表单的一些特性
import { Router } from '@angular/router';
import { AccountService } from '../../services/account.service';
import { environment } from '../../../../../environments/environment';
import { flyIn } from '../../../../animation/flyIn';
import { Observable } from 'rxjs/Observable';
@Component({
  selector: 'app-login',
  templateUrl: './login.component.html',
  styleUrls: ['./login.component.scss'],
  animations: [flyIn]
})
export class LoginComponent implements OnInit, OnDestroy {
  public form: FormGroup; // 表单对象
  public showLoading = false;
  public messageTips: string;
  public login_subscribe: any;

  // Validators的写法注意事项
  // v2.x版本号这种写法是可行的。v4有调整，不然不会生效
  // 'UserName':'', [ Validators.compose([Validators.minLength(6)] 

  // v4+ , 第一位的''代表这个元素初始化构建为空值,相似未输入状态
  // 'UserName': ['', Validators.compose([Validators.minLength(6)]

  // Validators可选參数
  // 1. required ：必须验证的。返回布尔值
  // 2. minLength ： 最小长度
  // 3. maxLenght: 最大长度
  // 4. nullValidator : 空值推断
  // 5. coompose :多重推断组合。以下有写法
  // 6. pattern是支持正则模式，正则谨记转义转义转义
  constructor(private fb: FormBuilder, private router: Router, private account: AccountService) {
    this.form = fb.group({
      'UserName': ['', Validators.compose([Validators.minLength(6) || Validators.pattern('(0|86|17951)?(-)?1[3,4,5,7,8,9]\\d{9}') || Validators.pattern('[\\.a-zA-Z0-9_-]+@[a-zA-Z0-9_-]+(\\.[a-zA-Z0-9_-]+)+')])],
      'PassWord': ['', Validators.compose([Validators.required, Validators.pattern('\\w{8,16}')])],
      'rememberAccount': ['']
    });
  }

  ngOnInit() {

  }

  // 登录事件
  onSubmit(e) {

    this.showLoading = true;
    this.login_subscribe = this.account.login(e.value).subscribe((res) => {
     console.log('省略。

。

。。。。')
    }, (err) => {
      this.showLoading = false;
    });
  }

  ngOnDestroy() {
    if (this.login_subscribe) {
      this.login_subscribe.unsubscribe();
    }
  }

}

效果图

---

嵌套表单

有些时候我们接口数据层次不可能唯独一层，出现两层三层都有可能；

这时候须要我们构建一个嵌套表单。。。

• html

v2-的写法：表单的取值能够用controls直接点出来

<div class="custom-card">
  <div class="custom-card-body">
    <form [formGroup]="form" (ngSubmit)="onSubmit(form.value)">
      <div class="row" formGroupName="RuleContent">
        <div class="col-sm-12 col-md-12 col-lg-8  offset-lg-2">
          <div class="form-group row" [ngClass]="{ 'has-danger': form.controls.RuleContent.controls.FenceName.invalid && form.controls.RuleContent.controls.FenceName.value ,'has-success': form.controls.RuleContent.controls.FenceName.valid && form.controls.RuleContent.controls.FenceName.value }">
            <label tooltip="" class="col-sm-10 col-md-3 form-control-label col-lg-3 star">速度栅栏名称</label>
            <div class="col-sm-8 col-md-6 col-lg-6">
              <input type="text" class="form-control" formControlName="FenceName" placeholder="栅栏名称">
            </div>
            <div class="col-2 col-sm-4 col-lg-3 flex-align-center">
              不超过十个字
            </div>
          </div>
          <div class="form-group row" [ngClass]="{ 'has-danger': form.controls.RuleContent.controls.MaxSpeed.invalid && form.controls.RuleContent.controls.MaxSpeed.value ,'has-success': form.controls.RuleContent.controls.MaxSpeed.valid && form.controls.RuleContent.controls.MaxSpeed.value }">
            <label tooltip="" class="col-sm-10 col-md-3 form-control-label col-lg-3 star">速度阈值</label>
            <div class="col-sm-8 col-md-6 col-lg-6">
              <input type="number" class="form-control" min="1" formControlName="MaxSpeed" placeholder="整数">
            </div>
            <div class="col-2 col-sm-4 col-lg-3 flex-align-center">
              km/h
            </div>
          </div>
          <div class="form-group row">
            <div class="col-12 col-sm-10 col-md-6 offset-sm-2 offset-md-4 offset-lg-3">
              <button type="submit" class="btn btn-primary" [disabled]="form.invalid">保存</button>
              <button type="button" class="btn btn-secondary" (click)="back()">取消</button>
            </div>
          </div>
        </div>
      </div>
    </form>

  </div>
</div>

v4+的写法 :嵌套表单的取值必须用.get()来获取，不然会报错误。详细原因是api修改了，看下官方文档就知道，修改了挺多(不只这块)

<div class="custom-card">
  <div class="custom-card-body">
    <form [formGroup]="form" (ngSubmit)="onSubmit(form.value)">
      <div class="row" formGroupName="RuleContent">
        <div class="col-sm-12 col-md-12 col-lg-8  offset-lg-2">
          <div class="form-group row" [ngClass]="{ 'has-danger': form.get('RuleContent.FenceName').invalid && form.get('RuleContent.FenceName').value ,'has-success': form.get('RuleContent.FenceName').valid && form.get('RuleContent.FenceName').value }">
            <label tooltip="" class="col-sm-10 col-md-3 form-control-label col-lg-3 star">速度栅栏名称</label>
            <div class="col-sm-8 col-md-6 col-lg-6">
              <input type="text" class="form-control" formControlName="FenceName" placeholder="栅栏名称">
            </div>
            <div class="col-2 col-sm-4 col-lg-3 flex-align-center">
              不超过十个字
            </div>
          </div>
          <div class="form-group row" [ngClass]="{ 'has-danger': form.get('RuleContent.MaxSpeed').invalid && form.get('RuleContent.MaxSpeed').value ,'has-success': form.get('RuleContent.MaxSpeed').valid && form.get('RuleContent.MaxSpeed').value }">
            <label tooltip="" class="col-sm-10 col-md-3 form-control-label col-lg-3 star">速度阈值</label>
            <div class="col-sm-8 col-md-6 col-lg-6">
              <input type="number" class="form-control" min="1" formControlName="MaxSpeed" placeholder="整数">
            </div>
            <div class="col-2 col-sm-4 col-lg-3 flex-align-center">
              km/h
            </div>
          </div>
          <div class="form-group row">
            <div class="col-12 col-sm-10 col-md-6 offset-sm-2 offset-md-4 offset-lg-3">
              <button type="submit" class="btn btn-primary" [disabled]="form.invalid">保存</button>
              <button type="button" class="btn btn-secondary" (click)="back()">取消</button>
            </div>
          </div>
        </div>
      </div>
    </form>

  </div>
</div>

• components.ts

import { Component, OnInit } from '@angular/core';
import { Router, ActivatedRoute } from '@angular/router';
import { FormGroup, FormControl, Validators, FormBuilder } from '@angular/forms'; // 引入表单的一些特性

// 动画
import { fadeIn } from '../../../../../animation/fadeIn';

// 服务
import { SpeedFenceService } from '../speed-fence.service';
import { EventsService } from '../../../../../services/events-service.service';

@Component({
  selector: 'app-modify',
  templateUrl: './modify.component.html',
  styleUrls: ['./modify.component.scss'],
  animations: [fadeIn]
})
export class ModifyComponent implements OnInit {
  public form: FormGroup;
  public getId: any;
  public id: number;
  constructor(
    private speedFenceService: SpeedFenceService,
    private eventsService: EventsService,
    private router: Router,
    private activatedRoute: ActivatedRoute,
    private fb: FormBuilder
  ) {
    this.form = fb.group({
      'ID': 0,
      'RuleContent': this.fb.group({
        'MaxSpeed': [0, Validators.compose([Validators.required, Validators.pattern('(([4-9][0-9])|(1[0-1][0-9])|(120))')])],
        'FenceName': ['', Validators.compose([Validators.required, Validators.minLength(2), Validators.maxLength(10)])],
      })

    });
  }

  ngOnInit() {
    this.checkAction();
    // console.log(this.form);
  }

  // 获取ID
  checkAction() {
    this.activatedRoute.params.subscribe((params: { id: string }) => {
      console.log(params);
      if (params.id) {
        console.log(this.id);
        this.id = parseInt(params.id, 10);
        this.form.controls['ID'].setValue(this.id);
        this.GetSpeedFenceSettingByFenceId({ FenceId: parseInt(params.id, 10) });
      }
    });
  }

  GetSpeedFenceSettingByFenceId(data) {
    this.speedFenceService.GetSpeedFenceSettingByFenceId(data).subscribe(
      res => {
        if (res.State) {
          this.form.controls['RuleContent'].setValue({
            'MaxSpeed': res.Data.RuleContent.MaxSpeed || '',
            'FenceName': res.Data.RuleContent.FenceName || '',
          });
        }
      },
      err => { }
    );
  }

  onSubmit(form) {
    console.log('此处省略。。。。

。');

  }

  // 取消
  back() {
    if (this.id) {
      this.router.navigate(['../../'], { relativeTo: this.activatedRoute });
    } else {
      this.router.navigate(['../'], { relativeTo: this.activatedRoute });
    }
  }

}

总结

多看手冊多动手,才是真理。。

有不足之处或者错误之处请留言指出，会及时跟进修正。。

谢谢