动态加载现有组件Angular 2 Final Release

Question

I'm trying to load dynamically a component in the final release 2.0.0.

Using RC5 I was loading using the following code:

Create a directive to load the controls:

import {
  CheckboxComponent, CheckboxListComponent,DatePickerComponent
} from '../components/';

@Directive({
      selector: '[ctrl-factory]'
    })
    export class ControlFactoryDirective implements OnChanges {
      @Input() model: any;

      constructor(private vcRef: ViewContainerRef, private resolver: ComponentResolver) {
      }

      create(cp) {
        this.resolver.resolveComponent(cp)
          .then(factory => {
            const injector = ReflectiveInjector.fromResolvedProviders([], this.vcRef.parentInjector);
            this.vcRef.createComponent(factory, 0, injector, []);
            let ch = this.vcRef.createComponent(factory, 0, injector, []).instance;
            ch.model = this.model;
        });
      }

      ngOnChanges() {
        if (!this.model) return;

        switch (this.model.type) {
          case 'checkbox':
            this.create(CheckboxComponent);
            break;
          case 'checkboxlist':
            this.create(CheckboxListComponent);
            break;
          case 'datepicker':
            this.create(DatePickerComponent);
            break;
          default:
            break;
        }
      }
    }

Then loaded that directive in my page like this:

<div ctrl-factory *ngFor="let child of page.childrens" [model]="child"></div>

But after updating from rc5 to 2.0.0 final release, the resolver doesn't exist anymore, was replaced by compiler.

I found loads of places showing how to load it using different codes, but all those too complex and I couldn't make it work.

Take this for instance: How can I use/create dynamic template to compile dynamic Component with Angular 2.0?

It looks more specific to that scenario, my one I just need to load the component and set an @Input called model.

One thing when I was trying I had to create dynamically a module for each component, then add the component to it. But then I had issues saying that the component was being set in more than one Module, try to remove in some place an not working.

The major part of the code shown, I get from this link: http://blog.lacolaco.net/post/dynamic-component-creation-in-angular-2-rc-5/

And did a couple of changes.

Update

I manage to make it work, using the following approach:

The create method has been changed to

private create(cp) {
    @NgModule({
      imports: [BrowserModule, ControlsModule],
      declarations: []
    })
    class DynamicModule {}

    this.compiler.compileModuleAndAllComponentsAsync(DynamicModule)
      .then(({componentFactories}) => {
        const compFactory = componentFactories.find(x => x.componentType === cp);
        const injector = ReflectiveInjector.fromResolvedProviders([], this.vcRef.parentInjector);
        const cmpRef = this.vcRef.createComponent(compFactory, 0, injector, []);
        cmpRef.instance.model = this.model;
      });
  }

Most places I've found, set create the Component and set it to the DynamicModule, the issue with that is when you are already declaring that same component in a different module, angular is going to complain about. The solution in my case was to import the my ControlsModule that has all my controls being exported.

Answer 1

Update

NgComponentOutlet was introduced in 4.0.0-beta.3 https://github.com/angular/angular/commit/8578682

Coming soon NgComponentOutlet

I see two options to do that:

1) Using ComponentFactoryResolver .

It uses the already generated factory and the code looks something like this:

constructor(private vcRef: ViewContainerRef, private resolver: ComponentFactoryResolver) { }
create(comp) {
  const factory = this.resolver.resolveComponentFactory(comp);
  const compRef = this.vcRef.createComponent(factory);

  (<any>compRef).instance.model = this.model;
}

In this case we have to define dynamic component in declarations and entryComponents properties within decorator of module

@NgModule({
  imports:      [ BrowserModule ],
  declarations: [ AppComponent, DynamicComponent ],
  entryComponents: [DynamicComponent],
  bootstrap:    [ AppComponent ]
})
export class AppModule { }

• Dynamically Creating Components With Angular 2.0
• Plunker Example

2) Using Compiler

In this case we can only run module compilation by using compiler.compileModuleAndAllComponentsAsync and then find component from componentFactories array. Your directive might look like this:

constructor(private vcRef: ViewContainerRef, private loader: DynamicLoaderService) { }

create(comp) {
  this.loader.createComponentFactory(comp).then(factory => {
     const compRef = this.vcRef.createComponent(factory);

    (<any>compRef).instance.model = this.model;
  })
}

DynamicLoaderService is a global service that will load and store component factories.

@Injectable()
export class DynamicLoaderService {
  constructor(protected compiler: Compiler) {}

  private resolveCompHelper$ = new Subject<any>();
  private cache = new Map<string, ComponentFactory<any> | number>();

  public createComponentFactory(type: string) : Promise<ComponentFactory<any>> {
    let factory = this.cache.get(type);

    // if factory has been already loading
    if(factory === 1) {
      return new Promise((resolve) => {
        // waiting compilation of factory
        const subscriber = this.resolveCompHelper$.subscribe((data) => {
          if(type !== data.type) return;
          subscriber.unsubscribe();
          resolve(data.factory);
        });   
      });
    } 
    // factory exists in cache
    if (factory) {
      return new Promise((resolve) => resolve(factory));
    }

    const comp = typeMap[type];
    // factory startes loading
    this.cache.set(type, 1);
    return new Promise((resolve) => {
      this.compiler.compileModuleAndAllComponentsAsync(createComponentModule(comp))
        .then((moduleWithFactories: ModuleWithComponentFactories<any>) =>  {
            factory = moduleWithFactories.componentFactories
              .find(x => x.componentType === comp);
            this.cache.set(type, factory);
            this.resolveCompHelper$.next({ type, factory});

            resolve(factory);
        });
    });
  }
}

Plunker Example

Hope it helps you!

Answer 2

It was useful for me to see this option based on a Directive, but I found the one that fit my needs based on Components: https://www.ag-grid.com/ag-grid-angular-aot-dynamic-components/

Happy coding!