Angular-无法解析组件ng build --prod的所有参数

Question

I was trying to build my angular app but it fails because of this error

 ERROR in : Can't resolve all parameters for SimpleLookupAddEditFormComponent 
 in C:/Users/lastr/Source/Repos/SMATA/Code/ng/smata-ng/src/app/system- 
 list/simple-lookup-add-edit/simple-lookup-add-edit.component.ts: (?, [object 
 Object], [object Object], [object Object]).

Here is the code of the COMPONENT. This is a base component. Is there anything missing here? maybe problems with the constructor properties?

 import { Component, OnInit } from '@angular/core';
 import { SimpleLookupBaseService } from '../services/simple-lookup-base/simple-lookup-base.service';
 import { ActivatedRoute, Router } from '@angular/router';
 import validationEngine from "devextreme/ui/validation_engine";
 import notify from 'devextreme/ui/notify';

 @Component({
   selector: 'app-simple-lookup-add-edit',
   templateUrl: './simple-lookup-add-edit.component.html',
   styleUrls: ['./simple-lookup-add-edit.component.css']
 })
 export class SimpleLookupAddEditFormComponent implements OnInit {

   newSystemList: {};
   isEditMode:boolean = true;
   selectedSystemList: any;
   title: string;
   saveButtonText: string;
   isPopupVisible:boolean = false;
   entityId:any;

   constructor(
     protected _systemListTitle : string,
     protected _svc: SimpleLookupBaseService,
     protected _router: Router,
     protected _route: ActivatedRoute
   ) 
     {}
 ............
 .....
 }

Answer 1

ERROR in : Can't resolve all parameters for SimpleLookupAddEditFormComponent in C:/Users/lastr/Source/Repos/SMATA/Code/ng/smata-ng/src/app/system- list/simple-lookup-add-edit/simple-lookup-add-edit.component.ts: (?, [object Object], [object Object], [object Object]).

The ? question mark in the error message tells which parameter in the constructor is unknown.

constructor(
 protected _systemListTitle : string,
 protected _svc: SimpleLookupBaseService,
 protected _router: Router,
 protected _route: ActivatedRoute
) 

The first parameter is triggering the ? question mark.

The type string is not an injectable type. Angular injector uses the type of the parameters to infer what the injectable provider that should be used.

To inject a string parameter you have to provide a token in one of your NgModule definitions.

export const LIST_TITLE: InjectionToken<string> = new InjectionToken<string>('LIST_TITLE');

@NgModule({
   providers: [{provide: LIST_TITLE, useValue: 'My List Title'}]
})

Now you can manually inject the token into your constructor.

constructor(
 @Inject(LIST_TITLE) protected _systemListTitle : string,
 protected _svc: SimpleLookupBaseService,
 protected _router: Router,
 protected _route: ActivatedRoute
)