Programmatically pass on projected content to children? (that would be rendered into a otherwise)

Question

Say, I have a <hook> component that creates a child programmatically, how could I pass the content (that Angular would render into a <ng-content></ng-content> in hook's template) as ng-content to that child component instead (that may or may not decide to display it)?

<hook ...>
   Dynamic content should be passed to hook's programmatically created child
</hook>

I found a very helpful explanation about content projection, that shows how to pass projected content to a programmatically created component, which is one half of my problem. The missing link for me is still: How to access the content passed to hook to pass it on.

score 3 · Accepted Answer · answered Nov 07 '19 at 14:29

If I fully understood the problem, here could be a solution:

app.component.ts

@Component({
  selector: 'my-app',
  template: `
    <h1>App comp</h1>

    <hook>
      awesome content here
    </hook>
  `
})
export class AppComponent  { }

hook.component.ts

@Component({
  selector: 'hook',
  template: `
    <h2>Hook comp</h2>

  <ng-template #content>
    <ng-content></ng-content>
  </ng-template>

  <ng-container #vc></ng-container>
  `
})
export class HookComp {
  @ViewChild('content', { static: true, read: TemplateRef })
  contentTpl: TemplateRef<any>;
  @ViewChild('vc', { static: true, read: ViewContainerRef })
  vc: ViewContainerRef;

  constructor (
    private cfr: ComponentFactoryResolver,
    private injector: Injector,
  ) { }

  ngAfterViewInit () {
    this.createChildComp();
  }

  private createChildComp () {
    const compFactory = this.cfr.resolveComponentFactory(HookChildComp);
    const componentRef = this.vc.createComponent(compFactory);

    componentRef.instance.contentTpl = this.contentTpl;

    componentRef.changeDetectorRef.detectChanges();
  }
}

hook-child.component.ts

@Component({
  selector: 'hook-child',
  template: `
    <h3>Hook child comp</h3>

    <ng-container *ngTemplateOutlet="contentTpl"></ng-container>
  `
})
export class HookChildComp {
  contentTpl: TemplateRef<any>;
}

As you can see, I'm able to grab the hook's ng-content by wrapping it into an ng-template. Then, I can simply query for that template and pass it to the programmatically created child.

Programmatically pass on projected content to children? (that would be rendered into a otherwise)

1 Answers1

app.component.ts

hook.component.ts

hook-child.component.ts