将回调函数作为@输入传递给子组件，类似于AngularJS方式

Question

AngularJS具有

@Component({
    selector: 'suggestion-menu',
    providers: [SuggestService],
    template: `
    <div (mousedown)="suggestionWasClicked(suggestion)">
    </div>`,
    changeDetection: ChangeDetectionStrategy.Default
})
export class SuggestionMenuComponent {
    @Input() callback: Function;

    suggestionWasClicked(clickedEntry: SomeModel): void {
        this.callback(clickedEntry, this.query);
    }
}


<suggestion-menu callback="insertSuggestion">
</suggestion-menu>

Answer 1

在某些情况下，您可能需要由父组件执行业务逻辑。在下面的示例中，我们有一个子组件，它根据父组件提供的逻辑呈现表行：

@Component({
  ...
  template: '<table-component [getRowColor]="getColor"></table-component>',
  directives: [TableComponent]
})
export class ParentComponent {

 // Pay attention on the way this function is declared. Using fat arrow (=>) declaration 
 // we can 'fixate' the context of `getColor` function
 // so that it is bound to ParentComponent as if .bind(this) was used.
 getColor = (row: Row) => {
    return this.fancyColorService.getUserFavoriteColor(row);
 }

}

@Component({...})
export class TableComponent{
  // This will be bound to the ParentComponent.getColor. 
  // I found this way of declaration a bit safer and convenient than just raw Function declaration
  @Input('getRowColor') getRowColor: (row: Row) => Color;

  renderRow(){
    ....
    // Notice that `getRowColor` function holds parent's context because of a fat arrow function used in the parent
    const color = this.getRowColor(row);
    renderRow(row, color);
  }
}

所以，我想在这里展示两件事：

1. Fat箭头(=

Answer 2

更新

此答案是在Angular 2仍处于alpha状态且许多功能不可用/未记录时提交的。虽然下面的方法仍然有效，但这种方法现在已经完全过时了。我强烈建议大家接受以下答案。

原始答案

是的，事实上是这样，但是您需要确保其范围正确。为此，我使用了一个属性来确保这是我想要的。

@Component({
  ...
  template: '<child [myCallback]="theBoundCallback"></child>',
  directives: [ChildComponent]
})
export class ParentComponent{
  public theBoundCallback: Function;

  public ngOnInit(){
    this.theBoundCallback = this.theCallback.bind(this);
  }

  public theCallback(){
    ...
  }
}

@Component({...})
export class ChildComponent{
  //This will be bound to the ParentComponent.theCallback
  @Input()
  public myCallback: Function; 
  ...
}

Answer 3

我认为这是一个糟糕的解决方案。如果您想将函数传递到具有@Input（）的组件中，您需要的是装饰器。

export class SuggestionMenuComponent {
    @Output() onSuggest: EventEmitter<any> = new EventEmitter();

    suggestionWasClicked(clickedEntry: SomeModel): void {
        this.onSuggest.emit([clickedEntry, this.query]);
    }
}

<suggestion-menu (onSuggest)="insertSuggestion($event[0],$event[1])">
</suggestion-menu>