angular - 此构造函数与 Angular 依赖注入(inject)不兼容，因为它在参数列表索引 0 处的依赖无效

Question

在我的 Angular 9 应用程序中，我有一个抽象类:

export abstract class MyAbstractComponent {
  constructor(
    protected readonly cd: ChangeDetectorRef,
  ) {
    super();
  }

  // ...
}

和一个扩展它的组件:

@Component({
  // ...
})
export class MyConcreteComponent extends MyAbstractComponent {
  // ...
}

一切正常，除了测试，我收到以下错误:

Error: This constructor is not compatible with Angular Dependency Injection because its dependency at index 0 of the parameter list is invalid. This can happen if the dependency type is a primitive like a string or if an ancestor of this class is missing an Angular decorator.

Please check that 1) the type for the parameter at index 0 is correct and 2) the correct Angular decorators are defined for this class and its ancestors.

Answer 1

我们在迁移到版本 9 时遇到了同样的问题。最后我们发现我们忘记为一些抽象组件添加装饰器。 从 v9 开始，所有使用 Angular DI 的类都必须有一个 Angular 类级装饰器。

来自 Ivy compatibility examples 的示例:

前:

export class DataService {
  constructor(@Inject('CONFIG') public config: DataConfig) {}
}

@Injectable()
export class AppService extends DataService {...}

后:

@Injectable() // <--- THIS
export class DataService {
  constructor(@Inject('CONFIG') public config: DataConfig) {}
}

@Injectable()
export class AppService extends DataService {...}