圆形依赖注入角度2 [英] Circular dependency injection angular 2

问题描述

我一直在努力将服务注入对方。以下博客构造函数中的循环依赖和依赖注入是一种令人困惑的地方，它说

两个对象之一是隐藏另一个对象C

在将服务类注入对方时，我收到以下错误

无法解析PayrollService的所有参数：（SiteService，StorageService，
SweetAlertService，？）

  // abstractmodal.service.ts 
 @Injectable（）
 export abstract class AbstractModel {
 
 abstract collection = []; 
 
构造函数（private siteService：SiteService，private storageService：StorageService，
 private sweetalertService：SweetAlertService）{} 
 
 
 setCollectionEmpty（）{
 this.collection = []; 
} 
} 
 //account-payable.service.ts 
 @Injectable（）
 export class AccountPayableService extends AbstractModel {
 
 public collection = []; 
 
构造函数（private sS：SiteService，private stS：StorageService，private sws：SweetAlertService，
 private accpPoService：PayablePurchaseOrderService，private attachmentService：AttachmentService，
 private injectorService：InjectorService）{
 super（sS，stS，sws）; 
} 
} 
 //injector.service.ts 
 @Injectable（）
 export class InjectorService {
 constructor（private payrollService：PayrollService）{} 
 
 cleanPayrollCollection（）{
 this.payrollService.setCollectionEmpty（）; 
} 
} 
 //payroll.service.ts 
 @Injectable（）
 export class PayrollService extends AbstractModel {
 
 public collection = []; 
 
构造函数（private sS：SiteService，private stS：StorageService，private sws：SweetAlertService，
 private accpService：AccountPayableService）{
 super（sS，stS，sws）; 
} 
} 
  

您的意见和回答将不胜感激。 / p>

谢谢

解决方案

通过注入 Injector 而不是引起循环依赖的其中一个服务来解决环境依赖关系

  private payrollService：PayrollService; 
构造函数（/ * private payrollService：PayrollService * / inject：Injector）{
 setTimeout（（）=> this.payrollService = injector.get（PayrollService））; 
} 
  

I've been struggling around injecting services into each other. The following blog Circular Dependency in constructors and Dependency Injection is kind of confusing where it says

One of the two objects is hiding another object C

I get the following error while injecting Service class into each other

Can't resolve all parameters for PayrollService: (SiteService, StorageService, SweetAlertService, ?)

//abstractmodal.service.ts
@Injectable()
 export abstract class AbstractModel {

   abstract collection = [];

   constructor(private siteService: SiteService, private storageService: StorageService,
                private sweetalertService: SweetAlertService) {}


   setCollectionEmpty() {
      this.collection = [];
    }
}
//account-payable.service.ts
@Injectable()
export class AccountPayableService extends AbstractModel {

   public collection = [];

   constructor(private sS: SiteService,private stS: StorageService, private sws: SweetAlertService,
            private accpPoService: PayablePurchaseOrderService, private attachmentService: AttachmentService,
            private injectorService: InjectorService) { 
         super(sS, stS, sws);
     }
}
//injector.service.ts
@Injectable()
export class InjectorService {
   constructor(private payrollService: PayrollService) {}

   cleanPayrollCollection() {
     this.payrollService.setCollectionEmpty();
   }
}
//payroll.service.ts
@Injectable()
export class PayrollService extends AbstractModel {

   public collection = [];

   constructor(private sS: SiteService,private stS: StorageService, private sws: SweetAlertService,
            private accpService: AccountPayableService) { 
    super(sS, stS, sws);
   }
}

Your comments and answered will be appreciated a lot.

Thanks

解决方案

You can workaround circular dependencies by injecting Injector instead of one of the services that cause the circular dependency

private payrollService:PayrollService;
constructor(/*private payrollService:PayrollService*/ injector:Injector) {
  setTimeout(() => this.payrollService = injector.get(PayrollService));
}

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