Question

我有一个应用程序，可以接收用户的数据并以表格形式对其进行验证。在这种情况下，当验证为true时，将启用按钮，并被允许用户提交其订单。

我不知道为什么我的科目不起作用。我的意思是我可以.next(value)进入组件并投入使用，我可以console.log(value)检查其是否投入使用。

我可以看到正在接收服务，但是该接收的值未在我要使用它们的组件中进行订阅。我停止运行项目，但无法修复。这是我尝试过的：

AuthService.ts

  emailSubject=new Subject<string>();
  getEmail(value)
  {
    console.log(value);
    this.emailSubject.next(value); //prints email to the console correctly
  }

CarService.ts

export class CarService
{
    carrierSubject=new Subject<number>();
    orderSubject=new Subject<Order[]>();
    totalCostSubject=new Subject<number>();
    lastTotalCostSubject=new Subject<number>();
  getId(myIndex:number)
   {
    this.carrierSubject.next(myIndex);
   }
 setOrders(value)
   {
     console.log(value);
     this.orderSubject.next(value);
   }
  setTotalCost(value)
   {
     this.totalCostSubject.next(value);
   }
   lastSetTotalCost(value)
   {
     this.lastTotalCostSubject.next(value);
   }

CarPayment.ts

export class CarPaymentComponent implements OnInit {
  car:Car; 
  selectedCar:string;
  somePlaceholder : number = 0;
  myArray:Order[];
  email:string;
  constructor(private carService:CarService,private authService:AuthService) { }
  ngOnInit() {
    this.carService.carrierSubject.subscribe(value=>
      {  
         this.car=this.carService.getCar(value);
         this.selectedCar=this.car.brand;
      });
      this.carService.lastTotalCostSubject.subscribe(value=>
        {  
         this.somePlaceholder=value;
        });
        this.carService.orderSubject.subscribe(value=>
          { 
            this.myArray=value;
          }
          );
        this.authService.emailSubject.subscribe(value=>
          {
            this.email=value;
          });
    }
    onSubmit()
    {
      console.log("ORDER INFO")
      console.log('This order ordered by:'+this.email);
      console.log("Ordered Car:"+this.selectedCar);
      console.log("Ordered Parts:"+this.myArray);
      console.log("Total Cost:"+this.somePlaceholder);
    }
}

Answer 1

正如@lealceldeiro和@FatemeFazli提到的那样，您需要使用BehaviorSubject或ReplaySubject。您的代码无法正常工作的原因是，您的可观察对象尚未触发任何值。本质上，当您执行.subscribe时，您将陷入更改事件。但是就您而言，该更改尚未被触发。

AuthService.ts

import { Injectable } from '@angular/core';
import { BehaviorSubject } from 'rxjs'; //<----Add this line

@Injectable()
export class AuthService {
  emailSubject = new BehaviorSubject<string>("test@test.com"); //<--- provide an initial value here
  getEmail(value) {
    console.log(value);
    this.emailSubject.next(value); //prints email to the console correctly
  }
}

CarService.ts

import { Injectable } from '@angular/core';
import { BehaviorSubject } from 'rxjs';

@Injectable()
export class CarService {
  carrierSubject = new BehaviorSubject<number>(0); //<-- provide an initial value here
  orderSubject = new BehaviorSubject<Order[]>([]); //<-- provide an initial value here
  totalCostSubject = new BehaviorSubject<number>(0); //<-- provide an initial value here
  lastTotalCostSubject = new BehaviorSubject<number>(0); //<-- provide an initial value here

  getId(myIndex: number) {
    this.carrierSubject.next(myIndex);
  }
  setOrders(value) {
    console.log(value);
    this.orderSubject.next(value);
  }
  setTotalCost(value) {
    this.totalCostSubject.next(value);
  }
  lastSetTotalCost(value) {
    this.lastTotalCostSubject.next(value);
  }
}

主题不发出数据

1 个答案: