我正在尝试创建一个 Angular2 响应式表单，我必须在其中确认用户输入的电子邮件地址。这是 plunker 的链接

import { Component, OnInit } from '@angular/core';
import { FormControl, FormGroup, Validators } from '@angular/forms';
import { User } from './signup.interface';

@Component({
selector: 'signup-form',
template: `
    <form novalidate (ngSubmit)="onSubmit(user)" [formGroup]="user">
    <label>
        <span>Full name</span>
        <input type="text" placeholder="Your full name" formControlName="name">
    </label>
    <div class="error" *ngIf="user.get('name').touched && user.get('name').hasError('required')">
        Name is required
    </div>
    <div class="error" *ngIf="user.get('name').touched && user.get('name').hasError('minlength')">
        Minimum of 2 characters
    </div>
    <div formGroupName="account">
        <label>
        <span>Email address</span>
        <input type="email" placeholder="Your email address" formControlName="email">
        </label>
        <div
        class="error"
        *ngIf="user.get('account').get('email').hasError('required') && user.get('account').get('email').touched">
        Email is required
        </div>
        <label>
        <span>Confirm address</span>
        <input type="email" placeholder="Confirm your email address" formControlName="confirm">
        </label>
        <div
        class="error"
        *ngIf="user.get('account').get('confirm').hasError('required') && user.get('account').get('confirm').touched">
        Confirming email is required
        </div>
    </div>
    <button type="submit" [disabled]="user.invalid">Sign up</button>
    </form>
`
})
export class SignupFormComponent implements OnInit {
  user: FormGroup;
  constructor() {}
  ngOnInit() {
    this.user = new FormGroup({
    name: new FormControl('', [Validators.required, Validators.minLength(2)]),
      account: new FormGroup({
        email: new FormControl('', Validators.required),
        confirm: new FormControl('', Validators.required)
      })
    });
  }
  onSubmit({ value, valid }: { value: User, valid: boolean }) {
    console.log(value, valid);
  }
}

我想在这两个电子邮件字段不匹配时显示错误。

我如何使用 angular2 中的 react 形式为此行为创建这样的验证？

我看过一个帖子，它使用模板驱动的方法来做到这一点 here ，但我无法弄清楚如何使用响应式(Reactive)表单方法来做到这一点。

最佳答案

我已经使用 react 形式完成了密码匹配。您可以将其更改为电子邮件。只需更改电子邮件的验证器来代替密码。两者都是字符串，其他一切都相同，并在电子邮件中输入密码匹配错误。它会起作用

应用程序模块.ts

将这些添加到您的 app.module.ts 文件中以使用响应式表单

import { NgModule } from '@angular/core';
    import { BrowserModule } from '@angular/platform-browser';
    import { FormsModule, ReactiveFormsModule } from '@angular/forms';
    import { AppComponent } from './app.component';
    @NgModule({
      imports: [
        BrowserModule,
        FormsModule,
        ReactiveFormsModule,
     ],
    declarations: [
    AppComponent
     ]
  providers: [],
  bootstrap: [
    AppComponent
   ]
  })
export class AppModule {}

应用程序组件.ts

import { Component,OnInit } from '@angular/core';
import template from './add.component.html';
import { FormGroup,FormBuilder,Validators } from '@angular/forms';
import { matchingPasswords } from './validators';
@Component({
    selector: 'app',
    template
})
export class AppComponent implements OnInit {
    addForm: FormGroup;
    constructor(private formBuilder: FormBuilder) {
    }
    ngOnInit() {

    this.addForm = this.formBuilder.group({
            username: ['', Validators.required],
            email: ['', Validators.required],
            role: ['', Validators.required],
            password: ['', Validators.required],
            password2: ['', Validators.required] }, 
          { validator: matchingPasswords('password', 'password2') <-- replace args with email_1 and email_2
        })
    };

addUser() {
        if (this.addForm.valid) {
            var adduser = {
                username: this.addForm.controls['username'].value,
                email: this.addForm.controls['email'].value,
                password: this.addForm.controls['password'].value,
                profile: {
                    role: this.addForm.controls['role'].value,
                    name: this.addForm.controls['username'].value,
                    email: this.addForm.controls['email'].value
                }
            };
          console.log(adduser);// adduser var contains all our form values. store it where you want 
            this.addForm.reset();// this will reset our form values to null 
        }
    }  
}

app.component.html

<div>
  <form [formGroup]="addForm">
   <input type="text" placeholder="Enter username" formControlName="username" />
   <input type="text" placeholder="Enter Email Address" formControlName="email"/>
   <input type="password" placeholder="Enter Password" formControlName="password" />
   <input type="password" placeholder="Confirm Password" name="password2" formControlName="password2"/>
   <div class='error' *ngIf="addForm.controls.password2.touched">
    <div class="alert-danger errormessageadduser" *ngIf="addForm.hasError('mismatchedPasswords')">                                  Passwords do not match
  </div>
</div>
<select name="Role" formControlName="role">
    <option value="admin" >Admin</option>
    <option value="Accounts">Accounts</option>
    <option value="guest">Guest</option>
</select>
<br/>
<br/>
<button type="submit" (click)="addUser()"><span><i class="fa fa-user-plus" aria-hidden="true"></i></span> Add User </button>
</form>
</div>

验证器.ts

export function matchingPasswords(passwordKey: string, confirmPasswordKey: string) {
    return (group: ControlGroup): {
        [key: string]: any
    } => {
        let password = group.controls[passwordKey];
        let confirmPassword = group.controls[confirmPasswordKey];

        if (password.value !== confirmPassword.value) {
            return {
                mismatchedPasswords: true
            };
        }
    }
}

关于javascript - Angular2 react 形式确认值相等，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/41138925/