Angular 解析器无法正常工作 ()

Question

我在一个新项目中遇到了这个问题。我创建了一条路线：

const routes: Routes = [
    {
        path: '',
        component: CategoriesComponent,
    },
    {
        path: ':categoryId',
        component: CategoryComponent,
        resolve: CategoryResolver,
    },
];

如您所见，它正在尝试使用如下所示的解析器：

import { Injectable } from '@angular/core';
import { ActivatedRouteSnapshot, Resolve, RouterStateSnapshot } from '@angular/router';
import { Observable } from 'rxjs';

import { Category, CategoryService } from '@situlive/angular/data';

@Injectable({
    providedIn: 'root',
})
export class CategoryResolver implements Resolve<Category> {
    constructor(private categoryService: CategoryService) {}

    resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<Category> {
        return this.categoryService.get(route.paramMap.get('categoryId'));
    }
}

当我使用这段代码时，出现错误：

Uncaught (in promise): NullInjectorError: R3InjectorError(CategoriesModule)[() => [ -> () => [ -> () => [ -> () => [ -> () => []: NullInjectorError: No provider for () => [!

如果我这样注释掉解析器：

const routes: Routes = [
    {
        path: '',
        component: CategoriesComponent,
    },
    {
        path: ':categoryId',
        component: CategoryComponent,
        //resolve: CategoryResolver,
        children: [
            {
                path: 'criteria',
                loadChildren: () => import('../criteria/criteria.module').then((m) => m.CriteriaModule),
            },
            {
                path: 'feeds',
                loadChildren: () => import('../feeds/feeds.module').then((m) => m.FeedsModule),
            },
            {
                path: 'fields',
                loadChildren: () => import('../fields/fields.module').then((m) => m.FieldsModule),
            },
        ],
    },
];

我不再收到错误，但显然什么都没有解决。我的 CategoryComponent 中的代码如下所示：

ngOnInit(): void {
    this.getCategory();
}

private getCategory(): void {
    this.category = this.route.snapshot.data.category;
}

有谁知道为什么会这样？

Answer 1

您首先需要修正您的路线定义。这可能是问题所在。尝试更改：

    {
        path: ':categoryId',
        component: CategoryComponent,
        resolve: CategoryResolver,
    }

至：

    {
        path: ':categoryId',
        component: CategoryComponent,
        resolve: {
          category: CategoryResolver
        },
    }

因为 resolve 需要是一个对象，而不是像您可以看到的那样直接引用 resolver here

Angular 解析器无法正常工作 ()

Angular Resolver not working no provider for ()

angular

angular-resolver