Angular 如何在自定义控件组件中触摸内部控件？

Question

我有一个带有我自己的自定义控件组件的表单：

@Component({
  selector: "my-app",
  template: `
    <form [formGroup]="form">
      <app-custom-control formControlName="customControl"></app-custom-control>
    </form>

    <button (click)="touch()">
      Touch!
    </button>
  `,
  styleUrls: ["./app.component.css"]
})
export class AppComponent {
  form: FormGroup;

  constructor(private fb: FormBuilder) {}

  ngOnInit() {
    this.form = this.fb.group({
      customControl: "1"
    });
  }

  touch() {
    this.form.markAllAsTouched();
  }
}

我的自定义控件组件内部有另一个自定义控件组件（在我的真实应用程序中需要它，因为外部控件组件有两种模式 - 读取和编辑）：

@Component({
  selector: "app-custom-control",
  template: `
    <ng-select [ngModel]="value" [items]="items"></ng-select>
  `,
  styleUrls: ["./custom-control.component.css"],
  providers: [
    {
      provide: NG_VALUE_ACCESSOR,
      useExisting: CustomControlComponent,
      multi: true
    }
  ]
})
export class CustomControlComponent implements ControlValueAccessor, OnInit {
  items = ["1", "2"];

  value = null;
  onChange = (value: any) => {};
  onTouched = () => {};

  constructor() {}

  registerOnChange(fn: any) {
    this.onChange = fn;
  }

  registerOnTouched(fn: () => {}): void {
    this.onTouched = fn;
  }

  writeValue(outsideValue: number) {
    this.value = outsideValue;
  }
}

可以将 NG_VALIDATORS 添加到 CustomControlComponent 并实现组件的验证方式（它可以只提升 ng-select 错误）。但是我真的不知道在包装表单的组件中执行 this.form.markAllAsTouched() 时如何触摸内部组件 (ng-select)。

我尝试在 ngDoCheck 生命周期方法中进行操作，但它似乎运行了太多次，这是不可接受的解决方案。

游乐场：https://stackblitz.com/edit/angular-ivy-u3kdfj

Answer 1

github中有几个相关问题：

您可以为 ControlValueAccessor 控件(outerControl) 和内部 NgModel 控件(innerControl) 获取 NgControl:

自定义-control.component.ts

export class CustomControlComponent implements ControlValueAccessor, AfterViewInit {
  @ViewChild(NgControl) innerNgControl: NgControl;

  constructor(private inj: Injector) {}

  ...

  ngAfterViewInit() { 
    const outerControl = this.inj.get(NgControl).control;
    ...
  }
}

然后你可以使用这个技巧将触摸状态绕过内部控制：

const prevMarkAsTouched = outerControl.markAsTouched;
outerControl.markAsTouched = (...args: any) => { 
  this.innerNgControl.control.markAsTouched();
  prevMarkAsTouched.bind(outerControl)(...args);
};

Forked Stackblitz

Angular 如何在自定义控件组件中触摸内部控件？

How to touch inner control in custom control component in Angular?

typescript

angular2-forms

angular

angular-forms