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angularangular-components

Creating an angular2 component with ng-content dynamically


I would like to set the body of <ng-content> while instantiating a component dynamically using ComponentFactoryResolver.

I see that I can get access to input & output using ComponentRef, but not a way to set <ng-content>.

Please note <ng-content> I'm planning on setting can contain simple text/can span dynamically created components

@Component({
    selector: 'app-component-to-project',
    template: `<ng-content></ng-content>`
})
export class ComponentToProject implements AfterContentInit {

    ngAfterContentInit() {
        // We will do something important with content here
    }

}


@Directive({
    selector: 'appProjectionMarker'
})
export class ProjectionMarkerDirective implements OnInit {

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

    ngOnInit() {
        const componentFactory: ComponentFactory<ComponentToProject> = this.componentFactoryResolver.resolveComponentFactory(ComponentToProject);
        const componentRef: ComponentRef<ComponentToProject> = this.viewContainerRef.createComponent(componentFactory);
        // Question: How to set content before the child's afterContentInit is invoked
    }

}

@Component({
    selector: 'appTestComponent',
    template: `<div appProjectionMarker></div>`
})
export class TestComponent {}

Solution

  • There is the projectableNodes parameter for the vcRef.createComponent method

    createComponent<C>(componentFactory: ComponentFactory<C>, index?: number, injector?: Injector, projectableNodes?: any[][], ngModule?: NgModuleRef<any>): ComponentRef<C>;
    

    You can use it to dynamically inject one component into another.

    Let's say we have the following component

    @Component({
        selector: 'card',
        template: `
            <div class="card__top">
                <h2>Creating a angular2 component with ng-content dynamically</h2>
            </div>
            <div class="card__body">
                <ng-content></ng-content>
            </div>
            <div class="card__bottom">
                <ng-content></ng-content>
            </div>
        `
    })
    export class CardComponent {}
    

    We want to create it dynamically and insert some controls to its ng-content locations. It could be done like follows:

    const bodyFactory = this.cfr.resolveComponentFactory(CardBodyComponent);
    const footerFactory = this.cfr.resolveComponentFactory(CardFooterComponent);
    
    let bodyRef = this.vcRef.createComponent(bodyFactory);
    let footerRef = this.vcRef.createComponent(footerFactory);
    
    const cardFactory = this.cfr.resolveComponentFactory(CardComponent);
    
    const cardRef = this.vcRef.createComponent(
        cardFactory,
        0,
        undefined,
        [
            [bodyRef.location.nativeElement],
            [footerRef.location.nativeElement]
        ]
    );
    

    Plunker Example

    See also