Angular

Question

我试图将索引从 ngFor 传递到我的 ts 文件，但没有成功。我实际上不知道该怎么做。有人能告诉我如何将索引值从 html 传递到 ts 文件吗？我认为使用 @Input 将是解决方案，但没有任何反应...... 谢谢

我的HTML:

<div *ngFor="let question of questions | async; index as i">{{question.libelle}}
     <div class="row text-left options">
        <div class="col-md-6" *ngFor="let reponse of reponses | async">
          <div class="option">
            <label class="" [attr.for]="reponse.id">
                <input type="checkbox" [(ngModel)]="reponse.Selected"/>
                {{reponse.libelle}}
            </label>
          </div>
        </div>
      </div>
      {{i}}
    </div>

我的TS:

@Injectable()


@Component({
  selector: 'app-java',
  templateUrl: './java.component.html',
  styleUrls: ['./java.component.sass']
})
export class JavaComponent implements OnInit {
  @Input()  i : any;
  questions :any = [];
  reponses :any = [];
  constructor(private questionnaireService: QuestionnaireService) { }

  ngOnInit() {
    this.questions = this.questionnaireService.getQuestion();
    this.reponses = this.questionnaireService.getReponse(this.i);
  }  

}

Answer 1

您可以通过 3 个步骤实现这些

Keep the currentIndex in ts file

Set the currentIndex from the html

Call getter method from the *ngFor

在 ts

@Injectable()
@Component({
  selector: 'app-java',
  templateUrl: './java.component.html',
  styleUrls: ['./java.component.sass']
})
export class JavaComponent implements OnInit {
  @Input()  i : any;
  questions :any = [];
  reponses :any = [];
  constructor(private questionnaireService: QuestionnaireService) { }

  ngOnInit() {
    this.questions = this.questionnaireService.getQuestion();
  }  

   //Track the current Index
   public currentIndex;

   //Current Index Setter
   setCurrentIndex(index){
       this.currentIndex = index;
   }

  //Getter for response which will use currentIndex
  get responses(){
    return this.questionnaireService.getReponses(this.currentIndex)
  }

}

在html

   <div *ngFor="let question of questions | async; index as i">{{question.libelle}}
         <div class="row text-left options" #>

            {{setCurrentIndex(i)}} <-- Set the current Index -->

            <div class="col-md-6" *ngFor="let reponse of responses | async">
              <div class="option">
                <label class="" [attr.for]="reponse.id">
                    <input type="checkbox" [(ngModel)]="reponse.Selected"/>
                    {{reponse.libelle}}
                </label>
              </div>
            </div>
          </div>
          {{i}}
 </div>

Note : since you are using async pipe make sure all your results are Observable.

Answer 2

您似乎对索引变量上下文以及可观察对象的工作方式有基本的误解。将您的组件分成两个组件，一个用于管理和显示整个列表，另一个用于管理和显示 child 列表

parent (app-java):

HTML:

<div *ngFor="let question of questions | async; index as i">{{question.libelle}}
 <div class="row text-left options">
    <app-java-child [i]="i"></app-java-child>
  </div>
  {{i}}
</div>

TS:

@Component({
  selector: 'app-java',
  templateUrl: './java.component.html',
  styleUrls: ['./java.component.sass']
})
export class JavaComponent implements OnInit {
  questions :any = [];
  constructor(private questionnaireService: QuestionnaireService) { }

  ngOnInit() {
    this.questions = this.questionnaireService.getQuestion();
  }  

}

和 child:

HTML:

<div class="col-md-6" *ngFor="let reponse of reponses | async">
   <div class="option">
     <label class="" [attr.for]="reponse.id">
            <input type="checkbox" [(ngModel)]="reponse.Selected"/>
            {{reponse.libelle}}
     </label>
   </div>
</div>

TS:

@Component({
  selector: 'app-java-child',
  templateUrl: './java-child.component.html',
  styleUrls: ['./java-child.component.sass']
})
export class JavaChildComponent implements OnInit {
  @Input()  i : any;
  reponses :any = [];
  constructor(private questionnaireService: QuestionnaireService) { }

  ngOnInit() {
    this.reponses = this.questionnaireService.getReponse(this.i);
  }  

}

通过这种方式，您可以从初始 ngFor 获取索引并将其作为输入提供给 child，这样 children 就可以负责构建自己的响应数组。

Answer 3

通常

足以通过 ii，但是，在我的情况下， sub 中有一个 *ngIf，所以一团糟计数并使其未定义。我最终将 *ngIf 置于 *ngFor 之上的顶层。

Angular - *ngFor：从 ts 文件中的索引传递 i

Angular - *ngFor: Passing i from index in ts file

ngfor

您可以通过 3 个步骤实现这些

在 ts

在html