AngularJS有&参数,你可以把一个回调传递给一个指令(例如AngularJS的回调方式)。是否可以将回调函数作为@Input传递给Angular组件(如下所示)?如果不是,那最接近AngularJS的功能是什么?

@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>

当前回答

与Max Fahl给出的答案不同。

你可以将回调函数定义为父组件中的箭头函数,这样你就不需要绑定它了。

@Component({
  ...
  // unlike this, template: '<child [myCallback]="theCallback.bind(this)"></child>',
  template: '<child [myCallback]="theCallback"></child>',
  directives: [ChildComponent]
})
export class ParentComponent {

   // unlike this, public theCallback(){
   public theCallback = () => {
    ...
  }
}

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

其他回答

传递带有参数的方法,在模板中使用.bind

@Component({
  ...
  template: '<child [action]="foo.bind(this, 'someArgument')"></child>',
  ...
})
export class ParentComponent {
  public foo(someParameter: string){
    ...
  }
}

@Component({...})
export class ChildComponent{

  @Input()
  public action: Function; 

  ...
}

与Max Fahl给出的答案不同。

你可以将回调函数定义为父组件中的箭头函数,这样你就不需要绑定它了。

@Component({
  ...
  // unlike this, template: '<child [myCallback]="theCallback.bind(this)"></child>',
  template: '<child [myCallback]="theCallback"></child>',
  directives: [ChildComponent]
})
export class ParentComponent {

   // unlike this, public theCallback(){
   public theCallback = () => {
    ...
  }
}

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

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

@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,我想在这里演示两件事:

胖箭头(=>)代替.bind(this)来保存正确的上下文; 子组件中回调函数的类型安全声明。

SnareChops给出的另一个答案。

你可以在模板中使用.bind(this)来达到同样的效果。它可能没有那么干净,但它节省了几行。我现在使用的是angular 2.4.0

@Component({
  ...
  template: '<child [myCallback]="theCallback.bind(this)"></child>',
  directives: [ChildComponent]
})
export class ParentComponent {

  public theCallback(){
    ...
  }
}

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

例如,我使用了一个登录模态窗口,其中模态窗口是父窗口,登录表单是子窗口,登录按钮调用了父窗口的关闭函数。

父模态包含关闭模态的函数。这个父组件将close函数传递给登录子组件。

import { Component} from '@angular/core';
import { LoginFormComponent } from './login-form.component'

@Component({
  selector: 'my-modal',
  template: `<modal #modal>
      <login-form (onClose)="onClose($event)" ></login-form>
    </modal>`
})
export class ParentModalComponent {
  modal: {...};

  onClose() {
    this.modal.close();
  }
}

在子登录组件提交登录表单后,它使用父模块的回调函数关闭父模块

import { Component, EventEmitter, Output } from '@angular/core';

@Component({
  selector: 'login-form',
  template: `<form (ngSubmit)="onSubmit()" #loginForm="ngForm">
      <button type="submit">Submit</button>
    </form>`
})
export class ChildLoginComponent {
  @Output() onClose = new EventEmitter();
  submitted = false;

  onSubmit() {
    this.onClose.emit();
    this.submitted = true;
  }
}