Showing JSON data as a list in Angular 7

Question

Showing JSON data as a list in Angular 7

I'm encountering a problem trying to display JSON data in a list format. It seems like something is missing because the data isn't showing up. Below is the code I've been using:

Service:

 getData() {
    this.http.post('http://localhost/api/Acc/GetData', "").subscribe(res => {
    return res;
   });
 }

Component:

  constructor(private api: ApiService) {
     var data = api.getData();   
  }

Template:

<mat-list>
<mat-list-item *ngFor="let item of data">
<h4 matLine> {{item.Field1}} </h4>
</mat-list-item>
</mat-list>

Upon inspection, I can identify some areas that may be causing issues:

I am uncertain if getData is correctly returning the data.
I am unsure if the constructor is effectively storing the data. I have tried alternative methods but none seem to work.

angular typescript angular7

Answer 1

Answer №1

Learn how to retrieve a list of objects from a server in Angular's Tour of Heroes tutorial in section 6, titled HTTP - Get Heroes with HTTPClient:

/** GET heroes from the server */
getHeroes (): Observable<Hero[]> {
  return this.http.get<Hero[]>(this.heroesUrl)
}

For more information and guidance on importing necessary modules for this task, refer to the rest of the tutorial at https://angular.io/tutorial.

Answer 2

Learn how to retrieve a list of objects from a server in Angular's Tour of Heroes tutorial in section 6, titled HTTP - Get Heroes with HTTPClient:

/** GET heroes from the server */
getHeroes (): Observable<Hero[]> {
  return this.http.get<Hero[]>(this.heroesUrl)
}

For more information and guidance on importing necessary modules for this task, refer to the rest of the tutorial at https://angular.io/tutorial.

Answer 3

Answer №2

Ensure that your getData() method returns an Observable to handle asynchronous data fetching.

Within your component, subscribe to the Observable and display the received data accordingly.

@Component({
  selector: 'app-some-data',
  templateUrl: './some-data.component.html',
  styleUrls: ['./some-data.component.css']
})
export class SomeDataComponent implements OnInit {
  data: any[];

  constructor(private api: ApiService) { }

  ngOnInit() {
    this.api.getData().subscribe(data => this.data = data);
  }
}

<div>
  <div *ngFor="let item of data">{{item | json}}</div>
</div>

@Injectable({
  providedIn: 'root',
})
export class ApiService {

  // constructor, etc.

  getData(): Observable<any[]> {
    return this.http.post<any[]>('http://localhost/api/Acc/GetData', "");
  }
}

You can also use the async pipe in the HTML template to subscribe to the observable.

@Component({
  selector: 'app-some-data',
  templateUrl: './some-data.component.html',
  styleUrls: ['./some-data.component.css']
})
export class SomeDataComponent implements OnInit {
  data: Observable<any[]>;

  constructor(private api: ApiService) { }

  ngOnInit() {
    this.data = this.api.getData();
  }
}

<div *ngIf="(data | async) as items">
  <div *ngFor="let item of items">{{item | json}}</div>
</div>

Answer 4

Ensure that your getData() method returns an Observable to handle asynchronous data fetching.

Within your component, subscribe to the Observable and display the received data accordingly.

@Component({
  selector: 'app-some-data',
  templateUrl: './some-data.component.html',
  styleUrls: ['./some-data.component.css']
})
export class SomeDataComponent implements OnInit {
  data: any[];

  constructor(private api: ApiService) { }

  ngOnInit() {
    this.api.getData().subscribe(data => this.data = data);
  }
}

<div>
  <div *ngFor="let item of data">{{item | json}}</div>
</div>

@Injectable({
  providedIn: 'root',
})
export class ApiService {

  // constructor, etc.

  getData(): Observable<any[]> {
    return this.http.post<any[]>('http://localhost/api/Acc/GetData', "");
  }
}

You can also use the async pipe in the HTML template to subscribe to the observable.

@Component({
  selector: 'app-some-data',
  templateUrl: './some-data.component.html',
  styleUrls: ['./some-data.component.css']
})
export class SomeDataComponent implements OnInit {
  data: Observable<any[]>;

  constructor(private api: ApiService) { }

  ngOnInit() {
    this.data = this.api.getData();
  }
}

<div *ngIf="(data | async) as items">
  <div *ngFor="let item of items">{{item | json}}</div>
</div>

Showing JSON data as a list in Angular 7

Answer №1

Answer №2

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