要求选中复选框

Question

我想要一个按钮被禁用，直到使用FormBuilder for Angular检查复选框。我不想明确检查复选框的值，并且更愿意使用验证器，以便我可以简单地检查form.valid。

在下面的两个验证案例中，复选框都是

interface ValidationResult {
  [key:string]:boolean;
}

export class CheckboxValidator {
  static checked(control:Control) {
    return { "checked": control.value };
  }
}

@Component({
  selector: 'my-form',
  directives: [FORM_DIRECTIVES],
  template: `  <form [ngFormModel]="form" (ngSubmit)="onSubmit(form.value)">
    <input type="checkbox" id="cb" ngControl="cb">
    <button type="submit" [disabled]="!form.valid">
    </form>`
})

export class SomeForm {
  regForm: ControlGroup;

  constructor(fb: FormBuilder) {
    this.form = fb.group({
      cb: [ CheckboxValidator.checked ]
      //cb: [ false, Validators.required ] <-- I have also tried this
    });
  }

  onSubmit(value: any) {
    console.log('Submitted: ', this.form);
  }
}

Answer 1

.TS

@Component({
  selector: 'my-app', 
  template: `
    <h1>LOGIN</h1>
    <form [ngFormModel]="loginForm"  #fm="ngForm"  (submit)="doLogin($event)"> 

          <input type="checkbox" id="cb" ngControl="cb" #cb="ngForm" required>
          <button type="submit" [disabled]="!loginForm.valid">Log in</button>

          <br/>
              <div>Valid ={{cb.valid}}</div>
              <div>Pristine ={{cb.pristine}}</div>
              <div>Touch ={{cb.touched}}</div>
              <div>form.valid?={{loginForm.valid}}</div>
          <BR/>
          <BR/>

    </form>
    `,
  directives: [ROUTER_DIRECTIVES,FORM_DIRECTIVES,CORE_DIRECTIVES]
})

export class Login { 
  constructor(fb: FormBuilder) {
    this.loginForm = fb.group({
      cb: [false, Validators.required],
    //cb: ['',Validators.required] - this will also work.

    });
  }
  doLogin(event) {
    console.log(this.loginForm);
    event.preventDefault();
  }
}

Working Plunker。

如果需要更改，请告诉我。

Answer 2

您可以使用ValidatorPattern并检查右（布尔）值：

<input type="checkbox" [formControl]="myForm.controls['isTosRead']">

这是绑定：

this.myForm = builder.group({
        isTosRead: [false, Validators.pattern('true')]
    });

Answer 3

从Angular 2.3.1你可以使用Validators#requiredTrue：

零件：

this.formGroup = this.formBuilder.group({
  cb: [false, Validators.requiredTrue]
});

模板：

<form [formGroup]="formGroup">
  <label><input type="checkbox" formControlName="cb"> Accept it</label>
  <div style="color: red; padding-top: 0.2rem" *ngIf="formGroup.hasError('required', 'cb')">
    Required
  </div>
  <hr>
  <div>
    <button type="submit" [disabled]="formGroup.invalid">Submit</button>
  </div>
</form>

STACKBLITZ DEMO

Answer 4

我发现Validator.required对复选框无法正常工作。如果选中一个复选框然后取消选中它，即使取消选中，FormControl仍会将其显示为有效。我认为它只会检查你是否将它设置为某种东西，无论是真还是假。

这是一个可以添加到FormControl的快速简单验证器：

  mustBeChecked(control: FormControl): {[key: string]: string} {
    if (!control.value) {
      return {mustBeCheckedError: 'Must be checked'};
    } else {
      return null;
    }
  }

Answer 5

<h1>LOGIN</h1>
<form [formGroup]="signUpForm"> 
    <input type="checkbox" formControlName="cb">
    <button type="submit" [disabled]="!loginForm.valid" (click)="doLogin()">Log in</button>
</form>

export class Login { 
  public signUpForm: FormGroup;

  constructor(fb: FormBuilder) {
    this.signUpForm = fb.group({
      cb: [false, Validators.requiredTrue]
    });
  }
  doLogin() {

  }
}

Answer 6

这在Angular版本2.3.0中得到了解决。

只需使用：Validators.requiredTrue instead of Validators.required。

Answer 7

我有这个非常简单的例子：

在您的组件中：

login : FormGroup;

constructor(@Inject(FormBuilder)formBuilder : FormBuilder) {
this.login = formBuilder.group({userName: [null], password: [null],
staySignedIn: [false,Validators.pattern('true')]});
}

在您的HTML中：

<form [formGroup]="login" (ngSubmit)="onSubmit()">
    <div class="form-group">
        <input formControlName="userName" required>
    </div>
    <div class="form-group">
        <input formControlName="password" type="password" required>
    </div>
    <div>
        <label>
    <input formControlName="staySignedIn" checked="staySignedIn" type="checkbox"> bla
  </label>
    </div>
    <button type="submit">bla</button>
    <div >
        <a href>bla?</a>
    </div>
</form>