问如何以角度9按变量加载动态模块？

EN

export class DynamicQuestionComponent {
    constructor(
        private componentFactoryResolver: ComponentFactoryResolver,
        private viewContainerRef: ViewContainerRef
    ) {}

    @Input() form: FormBase;
    @Input() formgroup: FormGroup;
    @ViewChild('content', { read: ViewContainerRef, static: true }) content: ViewContainerRef;

    @Input() set question(qvalue){
        if (qvalue){
            this.content.clear();
            var compath = `./${qvalue.qType}-question.component`;
            var testpath = './proto-question.component';
            import('./proto-question.component').then( dyncomp => {
                const component = this.viewContainerRef.createComponent(this.componentFactoryResolver.resolveComponentFactory(dyncomp.ProtoQuestionComponent));
                (<any>component).instance.form = this.form;
                (<any>component).instance.question = qvalue;
                (<any>component).instance.formgroup = this.formgroup;
                this.content.insert(component.hostView);
                component.injector.get(ChangeDetectorRef).markForCheck();
            })
        }
    }
}

ERROR Error: Uncaught (in promise): Error: Cannot find module './proto-question.component'