处理 Angular 2 中动态创建的组件的 @Input 和 @Output

Question

如何为 Angular 2 中动态创建的组件处理/提供 @Input 和 @Output 属性？

这个想法是在调用 createSub 方法时动态创建（在这种情况下）SubComponent。分叉很好，但我如何为 SubComponent 中的@Input 属性提供数据。另外，如何处理/订阅 SubComponent 提供的@Output 事件？

示例： （两个组件在同一个 NgModule 中）

应用组件

@Component({
  selector: 'app-root'
})  
export class AppComponent {

  someData: 'asdfasf'

  constructor(private resolver: ComponentFactoryResolver, private location: ViewContainerRef) { }

  createSub() {
    const factory = this.resolver.resolveComponentFactory(SubComponent);
    const ref = this.location.createComponent(factory, this.location.length, this.location.parentInjector, []);
    ref.changeDetectorRef.detectChanges();
    return ref;
  }

  onClick() {
    // do something
  }
}

子组件

@Component({
  selector: 'app-sub'
})
export class SubComponent {
  @Input('data') someData: string;
  @Output('onClick') onClick = new EventEmitter();
}

Answer 1

createSub() {
  const factory = this.resolver.resolveComponentFactory(SubComponent);
  const ref = this.location.createComponent(factory, this.location.length, 
  ref.instance.model = {Which you like to send}
  ref.instance.outPut = (data) =>{ //will get called from from SubComponent} 
  this.location.parentInjector, []);
  ref.changeDetectorRef.detectChanges();
return ref;
}

SubComponent{
 public model;
 public outPut = <any>{};  
 constructor(){ console.log("Your input will be seen here",this.model) }
 sendDataOnClick(){
    this.outPut(inputData)
 }    
}

Answer 2

如果您知道要添加的组件的类型，我认为您可以使用其他方法。

在您的应用根组件 html 中：

<div *ngIf="functionHasCalled">
    <app-sub [data]="dataInput" (onClick)="onSubComponentClick()"></app-sub>
</div>

在您的应用根组件打字稿中：

private functionHasCalled:boolean = false;
private dataInput:string;

onClick(){
   //And you can initialize the input property also if you need
   this.dataInput = 'asfsdfasdf';
   this.functionHasCalled = true;
}

onSubComponentClick(){

}

Answer 3

为@Input 提供数据非常简单。您已将组件命名为 app-sub，并且它有一个名为 data 的 @Input 属性。可以通过这样做来提供这些数据：

<app-sub [data]="whateverdatayouwant"></app-sub>

Answer 4

我发现以下代码可以从字符串 (angular2 generate component from just a string) 动态生成组件，并从中创建了一个 compileBoundHtml 指令，该指令传递输入数据（不处理输出，但我认为同样的策略适用于你可以修改这个）：

    @Directive({selector: '[compileBoundHtml]', exportAs: 'compileBoundHtmlDirective'})
export class CompileBoundHtmlDirective {
    // input must be same as selector so it can be named as property on the DOM element it's on
    @Input() compileBoundHtml: string;
    @Input() inputs?: {[x: string]: any};
    // keep reference to temp component (created below) so it can be garbage collected
    protected cmpRef: ComponentRef<any>;

    constructor( private vc: ViewContainerRef,
                private compiler: Compiler,
                private injector: Injector,
                private m: NgModuleRef<any>) {
        this.cmpRef = undefined;
    }
    /**
     * Compile new temporary component using input string as template,
     * and then insert adjacently into directive's viewContainerRef
     */
    ngOnChanges() {
        class TmpClass {
            [x: string]: any;
        }
        // create component and module temps
        const tmpCmp = Component({template: this.compileBoundHtml})(TmpClass);

        // note: switch to using annotations here so coverage sees this function
        @NgModule({imports: [/*your modules that have directives/components on them need to be passed here, potential for circular references unfortunately*/], declarations: [tmpCmp]})
        class TmpModule {};

        this.compiler.compileModuleAndAllComponentsAsync(TmpModule)
          .then((factories) => {
            // create and insert component (from the only compiled component factory) into the container view
            const f = factories.componentFactories[0];
            this.cmpRef = f.create(this.injector, [], null, this.m);
            Object.assign(this.cmpRef.instance, this.inputs);
            this.vc.insert(this.cmpRef.hostView);
          });
    }
    /**
     * Destroy temporary component when directive is destroyed
     */
    ngOnDestroy() {
      if (this.cmpRef) {
        this.cmpRef.destroy();
      }
    }
}

重要的修改在于增加了：

Object.assign(this.cmpRef.instance, this.inputs);

基本上，它会将您希望在新组件上的值复制到 tmp 组件类中，以便它们可以在生成的组件中使用。

它会像这样使用：

<div [compileBoundHtml]="someContentThatHasComponentHtmlInIt" [inputs]="{anInput: anInputValue}"></div>

希望这可以节省我不得不做的大量谷歌搜索。

Answer 5

创建组件时可以轻松绑定：

createSub() {
    const factory = this.resolver.resolveComponentFactory(SubComponent);
    const ref = this.location.createComponent(factory, this.location.length, this.location.parentInjector, []);
    ref.someData = { data: '123' }; // send data to input
    ref.onClick.subscribe( // subscribe to event emitter
      (event: any) => {
        console.log('click');
      }
    )
    ref.changeDetectorRef.detectChanges();
    return ref;
  }

发送数据非常简单，只需 ref.someData = data 其中data 是您要发送的数据。

从输出中获取数据也很容易，因为它是一个EventEmitter，您可以简单地订阅它，并且只要您emit() 来自组件的值，您传入的clojure 就会执行。