Question

我有一个实现ControlValueAccessor的自定义表单组件。该组件具有触及的内部属性。

export class BmInputComponent implements ControlValueAccessor, Validator {

    private onTouchedCallback: () => {};
    private touched: boolean = false;

    registerOnTouched(fn: any) {
        this.onTouchedCallback = fn;
    }

    onBlur() {
        this.touched = true;
        this.onTouchedCallback();
    }
}

我需要实现像

这样的方法

markTouched() {
    this.touched = true;
}

当在formControl中执行markAsTouched时，组件的用户可以调用它：customInputControl.markAsTouched()

我无法找到一种方法来做到这一点。

@Edit：试图注入NgControl：

@Component({
    selector: 'bm-input',
    templateUrl: './bm-input.component.html',
    encapsulation: ViewEncapsulation.None,
    providers: [
         {
            provide: NG_VALUE_ACCESSOR,
            useExisting: forwardRef(() => BmInputComponent),
            multi: true
        }
    ]
})
export class BmInputComponent implements ControlValueAccessor, Validator {

    private onTouchedCallback: () => {};
    private touched: boolean = false;

    constructor(@Self() @Optional() public _formControl: NgControl) {
        this._viewDate = new Date();
        if (this._formControl) {
            this._formControl.valueAccessor = this;
            this._formControl.statusChanges.subscribe(this.markTouched);
        }
    }
    registerOnTouched(fn: any) {
        this.onTouchedCallback = fn;
    }

    onBlur() {
        this.touched = true;
        this.onTouchedCallback();
    }

    markTouched() {
        if(this._formControl.touched)
            this.touched = true;
    }

}

但是当使用formControl调用组件时，我得到Cannot instantiate cyclic dependency! NgControl。

Answer 1

您是否尝试过@SkipSelf（）而不是@Self（）？

Answer 2

您可以尝试以下方法：

constructor(private injector: Injector) {
}


ngDoCheck() {

    let ngControl = this.injector.get(NgControl);
    if (! ngControl.control) {
        return;
    }

    this.touched = ngControl.control.touched;

}

Angular 2自定义表单组件：提供markTouched方法

2 个答案: