显示编号导航栏上购物车中的商品在刷新时显示为 0

Question

So in my angular application. I am trying to add movies to a cart. I am able to add them to the cart, and the correct no. of movies in the cart are reflected back on the navbar, but on refresh, it turns to 0.

HTML of displaying count

 <li *ngIf="signedIn" class="nav-item" routerLinkActive="active"> <a class="nav-link" [routerLink]="['/cart',authService.decodedToken.nameid]">Cart <span class="badge badge-dark">{{cartItemCount}}</span></a> </li>

My shared service through which I am updating-

 export class SharedcartService { private currentCartCount = new BehaviorSubject(0); currentMessage = this.currentCartCount.asObservable(); constructor() { } addMovieToCart(movie: any) { sessionStorage.setItem('movie', JSON.stringify(movie)); } getMovieFromCart() { return JSON.parse(sessionStorage.getItem('movie')); } removeAllMovieFromCart() { return sessionStorage.removeItem('movie'); } updateCartCount(count: number) { this.currentCartCount.next(count); } }

My cart.ts file

 export class CartComponent implements OnInit { user: User; defaultQuantity: number = 1; movieAddedTocart: any; allTotal: number; constructor(private http:HttpClient, private userService: UserService,private sharedService: SharedcartService, private alertify: AlertifyService,private route: ActivatedRoute ) { } ngOnInit() { this.route.data.subscribe(data=>{ this.user=data['user']; }); this.movieAddedTocart=this.sharedService.getMovieFromCart(); for (let i in this.movieAddedTocart) { this.movieAddedTocart[i].Quantity = 1; } this.sharedService.removeAllMovieFromCart(); this.sharedService.addMovieToCart(this.movieAddedTocart); this.calculteAllTotal(this.movieAddedTocart); } onRemoveQuantity(movie: any) { this.movieAddedTocart=this.sharedService.getMovieFromCart(); this.movieAddedTocart.find(p=>p.aMovieId == movie.aMovieId).Quantity = movie.Quantity-1; this.sharedService.removeAllMovieFromCart(); this.sharedService.addMovieToCart(this.movieAddedTocart); this.calculteAllTotal(this.movieAddedTocart); } calculteAllTotal(allItems:any) { let total = 0; for (let i in allItems) { total= total+(allItems[i].Quantity *allItems[i].aPrice); } this.allTotal=total; } }

Answer 1

可能是因为 ngOnInit 它正在执行this.sharedService.removeAllMovieFromCart()从购物车中删除所有电影