警告:无法解析UsersPermissionsService的所有参数这将成为Angular v5.x中的错误

Question

当我运行build -prod时,我收到以下警告.

Warning: Can't resolve all parameters for UsersPermissionsService in C:/SourceControl/Test.Client/src/app/shared/users/users-permissions.service.ts: (?, ?, ?). This will become an error in Angular v5.x
Warning: Can't resolve all parameters for UsersPermissionsService in C:/SourceControl/Test.Client/src/app/shared/users/users-permissions.service.ts: (?, ?, ?). This will become an error in Angular v5.x

我的代码如下:

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

@Injectable()
export class UsersPermissionsService {

    public USERS_CREATE_PERMISSION: string = '';
    public USERS_UPDATE_PERMISSION: string = '';
    public USERS_DELETE_PERMISSION: string = '';

    constructor(public UsersCreatePermission: string,
        public UsersUpdatePermission: string,
        public UsersDeletePermission: string) {
        this.USERS_CREATE_PERMISSION = UsersCreatePermission;
        this.USERS_UPDATE_PERMISSION = UsersUpdatePermission;
        this.USERS_DELETE_PERMISSION = UsersDeletePermission;
    }
}


@Injectable()
export class UserModulePermissionsService extends UserPermissionsService {
    constructor() {
        super("ClientsCreate",
            "ClientsEdit",
            "ClientsDelete");
    }
}

@Component({
    templateUrl: './users-permissions.component.html',    
    providers: [UsersPermissionsService]
})
export class UsersPermissionsComponent {
    constructor(public usersPermissionsService: UsersPermissionsService) {

    }
}

在我的懒惰加载模块中,我有:

 providers: [
        { provide: UsersPermissionsService, useClass: UserModulePermissionsService }
    ]

现在,角度5已经出来,我将需要更新,并且消息说这个警告将成为错误.

不明白这里真正的问题是什么.

Answer 1

@Injectable从基类中删除装饰器.您应该只包括类,装饰(或与此有关的任何装饰),该角应直接实例(同时做,使用注射器也解决他们的构造函数的参数).

因为很明显,在你的情况下,基类不是直接用angular实例化的(它具有注入器不知道的构造函数参数),你应该从中删除装饰器.