从角形材质导入树组件

Question

我正在尝试从材料中导入树组件i，e Tree with partially loaded data。根据此示例，我遵循了stackblitz

我被这个错误困扰

ERROR Error: StaticInjectorError(AppModule)[ExistingOfferingsComponent->LoadmoreDatabase]: 
StaticInjectorError(Platform: core)[ExistingOfferingsComponent -> LoadmoreDatabase]: 
NullInjectorError: No provider for LoadmoreDatabase!

我该如何默认使第一个matTree（示例中为蔬菜）处于打开状态。

Answer 1

您需要将LoadmoreDatabase添加到providers组件的ExistingOfferings中：

@Component({
    selector: 'existing-offerings-component',
    templateUrl: 'existing-offerings-component.html',
    styleUrls: ['existing-offerings-component.css'],
    providers: [LoadmoreDatabase]
})
export class ExistingOfferingsComponent{
    ...
}