`Error: Output is not defined` when passing value outside a directive to parent directive

问题

I have an root-app component which is defined like this in the template.

template: `
<dev-table (complete)="onSelect(developer)"></dev-table>
<dev-details [selectedDeveloper]="selectedDeveloper"></dev-details>
`
directives: [DevDetailsComponent, DevTableComponent],
providers: [DevValueService, provide(DevService, {useClass: DevService})]

is a list and on selection of one of the internal list it should send the value of the list (developer) which is passed into as selected developer. @Input is defined right and is taken into correctly. But the @output is giving an error Error: Output is not defined What definition is needed or what is the definition method. I am missing something.

This is the class definition:

@Component({
  selector: 'dev-table',
  template: `
    <ul class="dev">
      <li *ngFor="#developer of developers"
        [class.selected]="developer === selectedDeveloper;this.complete.next();"
        (click)="onSelect(developer)">
        <span class="spanbackground">{{developer.name}}</span> -  {{developer.skill}}
      </li>
    </ul>  
  `, 
  providers: [DevService]
})

export class DevTableComponent implements OnInit{
    public developers : Developer[];
    public selectedDeveloper : Developer;
    constructor(private _DevService: DevService) { }
    @Output() complete = new EventEmitter(); 
    public onSelect(developer: Developer) { this.selectedDeveloper = developer; }
    getDevelopers(){
      this._DevService.getDevelopers().then(developers => this.developers = developers)
    }
    ngOnInit(){
      this.getDevelopers();
    }
}

UPDATED: The final working code did not have developer === selectedDeveloper;this.complete.next(); rather this.complete.next() was put into the onSelect function.

回答1:

"@output is giving an error Error: Output is not defined What definition is needed or what is the definition method. I am missing something." :

import {Output} from "angular2/core";

You have to import the definition of any class you are using.

回答2:

If you want to pass the value to the parent component you can leverage custom event. This code is located in the template of the parent component:

@Component({
  (...)
  template: `
    <dev-table (complete)="someMethod($event.value)"></dev-table>
  `
})
export class ParentComponent {
  someMethod(value) {
    console.log('complete event - value = ' + value);
  }
}

To trigger the event, you could do something like that in your child component:

@Component({
  (...)
  template: `
    (...)
    <span (click)="triggerCompleteEvent()">Trigger complete event</span>
  `
})
export class DevTableComponent implements OnInit{
  @Output()
  complete:EventEmitter;

  constructor() {
    this.complete = new EventEmitter();
  }

  triggerCompleteEvent() {
    this.complete.emit(someValue);
  }
}

someValue corresponds to the value you want the event contains and event subscribes can get.

Hope it helps you, Thierry

来源：https://stackoverflow.com/questions/34808134/error-output-is-not-defined-when-passing-value-outside-a-directive-to-parent

标签

events

output

angular