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正确的方法初始化被动窗体的输入字段并使控件有效

form-control angular-reactive-forms angular

HDJEMAI · 技术社区 · 6 年前

这里的问题应该很简单,但我无法初始化一个被动窗体的输入字段,并使该控件有效。

@Component({
  selector: 'app-profile-editor',
  templateUrl: './profile-editor.component.html',
  styleUrls: ['./profile-editor.component.css']
})
export class ProfileEditorComponent {
  profileForm = this.fb.group({
    firstName: string,
    lastName: string,

    address: this.fb.group({
      fName: ['initial value', [Validators.required]],
      city: ['', [Validators.required]],
      state: [''],
      zip: ['']
    }),
  });

  constructor(private fb: FormBuilder) { }
}

在模板中我可以说:

<input [(ngModel)]="firstName" formControlName="fName" />

fName: ['initial value', [Validators.required]],

第二种方法不起作用:

fName: new FormControl('initial value', [Validators.required])

第三种方法是 在模板中,这样做不起作用:

 <div>
    <input [(ngModel)]="firstName" formControlName="fName" [value]="'default value'"/>
 </div>

第四种方法是:

this.address.controls['fName'].setvalue('default value');
this.address.controls['fName'].updateValueAndValidity();

因此,即使在我的表单中,该字段最初已填充,并且我必须提供其他字段,但由于该字段,我的表单无效,因此它不会将我的保存按钮显示为已启用。

有人能解释为什么会有这样的行为,或者解释什么是正确的方法吗?

我必须清理这个例子,但这里有一个使用: <input type=“text”class=“表单控件”

https://stackblitz.com/edit/angular-reactive-forms-jhg6ds?file=app%2Fapp.component.ts

(稍后将更新此示例。)

1 回复 | 直到 4 年前

HDJEMAI 4 年前

编辑版本: https://stackblitz.com/edit/angular-reactive-forms-atvaym

模板:

<form [formGroup]="SignupForm" (ngSubmit)="onSubmit()">
    <div class="form-group">
        <label for="username">UserName</label>
        <input type="text" class="form-control" id="username" formControlName="username">
        <span class="help-block" *ngIf="!SignupForm.controls.username.valid && SignupForm['controls'].username.touched">
   <span *ngIf="SignupForm['controls'].username.hasError('nameIsForbidden')">name is invalid</span>
        <span *ngIf="SignupForm['controls'].username.hasError('required')">field is required</span>
        </span>
    </div>

    <div class="form-group">
        <label for="email">Email</label>
        <input type="email" class="form-control" id="email" formControlName="email">
        <span class="help-block" *ngIf="!SignupForm.controls.email.valid && SignupForm['controls'].email.touched">
   <span *ngIf="SignupForm['controls'].email.hasError('emailIsForbidden')">name is invalid</span>
        <span *ngIf="SignupForm['controls'].email.hasError('required')">field is required</span>
        </span>
    </div>

    <div class="radio" *ngFor="let gender of genders">
        <label>
<input type="radio" [value]="gender" formControlName = "gender">{{gender}}
</label>
    </div>

    <div formArrayName="hobbies">
        <h4>Hobbies</h4>
        <button class="btn btn-default" type="button" (click)="onAddHobby()">Add Hobby</button>
        <div class="form-group" *ngFor="let hobbyControl of SignupForm['controls'].hobbies['controls']; let i=index">
            <div [formGroupName]="i">
                <div [formGroup]="SignupForm['controls'].hobbies['controls'][i]">
                    <input type="text" class="form-control" formControlName="name">
                </div>
            </div>
        </div>
    </div>
    <span class="help-block" *ngIf="!SignupForm.valid && SignupForm.touched">please enter valid data</span>
    <button class="btn btn-primary" type="submit">Submit</button>
</form>

  ngOnInit(){
    this.SignupForm = this.fb.group({
      username: [{value: 'default name', disabled: false}, [Validators.required, this.validateName()]],
      email: [{value: 'default name', disabled: false}, [Validators.required, Validators.email, this.validateEmail()]],
      gender: [{value: 'female', disabled: false}, [Validators.required]],
      hobbies: this.fb.array([])
    });
  }

  onAddHobby(){
    const controls = <FormArray>this.SignupForm.controls['hobbies'];
    let control = this.fb.group({
      name: [{value: 'hobbi', disabled: false}]
    });
    
    controls.push(control);
  }

  private validateName(): ValidatorFn {
    return (control: AbstractControl): {[key: string]: any} => {
      for(let i of this.forbiddenUserNames){
        if(i === control.value){
          return {'nameIsForbidden': true};
        } else {
          return null;
        }
      }
    }
  }
    
  private validateEmail(): ValidatorFn {
    return (control: AbstractControl): {[key: string]: any} => {
      if(control.value === 'test@test.com'){
        return {'emailIsForbidden': true};
      } else {
        return null;
      }
    }
  }

我建议看一下这篇关于异步验证器的文章 https://alligator.io/angular/async-validators/