不能在 Angular 6 的子模块中使用 app 模块内声明的指令

Question

我正在使用Angular 6。

我通过扩展 NbgPopover 声明了一个指令 StickyPopover 并添加了 declaration 的 app.module.ts

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppComponent } from './app.component';
import { AppRoutingModule } from './app-routing.module';
import { AuthLayoutComponent } from './layouts/auth-layout/auth-layout.component';
import {AdminLayoutComponent} from './layouts/admin-layout/admin-layout.component';
import {FormsModule} from '@angular/forms';
import {RouterModule} from '@angular/router';
import {BrowserAnimationsModule} from '@angular/platform-browser/animations';
import {NgbModule} from '@ng-bootstrap/ng-bootstrap';
import {StickyPopoverDirective} from './sticky-popover.directive';


@NgModule({
  declarations: [
    AppComponent,
    AuthLayoutComponent,
    AdminLayoutComponent,
    StickyPopoverDirective           // custom created directive
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    BrowserAnimationsModule,
    FormsModule,
    HttpClientModule,
    RouterModule,
    NgbModule.forRoot(),
  ],
  providers: [],
  bootstrap: [AppComponent],
})
export class AppModule { }

并且该指令的位置与app.module.ts文件的位置处于同一级别。

sticky-popover.directive.ts的内容是

import {
  ElementRef,
  Directive, Input, TemplateRef,
  EventEmitter,
  Renderer2,
  Injector,
  ComponentFactoryResolver,
  ViewContainerRef,
  NgZone, OnInit, OnDestroy
} from '@angular/core';

import { NgbPopover, NgbPopoverConfig } from '@ng-bootstrap/ng-bootstrap';

@Directive({
  selector: '[appStickyPopover]',
  exportAs: 'stickyPopover'
})
export class StickyPopoverDirective extends NgbPopover implements OnInit, OnDestroy {
  @Input() stickyPopover: TemplateRef<any>;

  popoverTitle: string;

  placement: 'auto' | 'top' | 'bottom' | 'left' | 'right' | 'top-left' | 'top-right' | 'bottom-left' |
    'bottom-right' | 'left-top' | 'left-bottom' | 'right-top' | 'right-bottom' | ('auto' | 'top' | 'bottom' |
    'left' | 'right' | 'top-left' | 'top-right' | 'bottom-left' | 'bottom-right' | 'left-top' | 'left-bottom' |
    'right-top' | 'right-bottom')[];

  triggers: string;

  container: string;

  shown: EventEmitter<{}>;

  hidden: EventEmitter<{}>;

  ngpPopover: TemplateRef<any>;

  canClosePopover: boolean;

  toggle(): void {
    super.toggle();
  }

  isOpen(): boolean {
    return super.isOpen();
  }



  constructor(
    private _elRef: ElementRef,
    private _render: Renderer2,
    injector: Injector,
    componentFactoryResolver: ComponentFactoryResolver,
    private viewContainerRef: ViewContainerRef,
    config: NgbPopoverConfig,
    ngZone: NgZone
  ) {
    super(_elRef, _render, injector, componentFactoryResolver, viewContainerRef, config, ngZone, document);
    this.triggers = 'manual';
    this.popoverTitle = 'Permissions';
    this.container = 'body';
  }

  ngOnInit(): void {
    super.ngOnInit();
    this.ngbPopover = this.stickyPopover;

    this._render.listen(this._elRef.nativeElement, 'mouseenter', () => {
      this.canClosePopover = true;
      this.open();
    });

    this._render.listen(this._elRef.nativeElement, 'mouseleave', (event: Event) => {
      setTimeout(() => { if (this.canClosePopover) { this.close(); } }, 100);

    });

    this._render.listen(this._elRef.nativeElement, 'click', () => {
      this.close();
    });
  }

  ngOnDestroy(): void {
    super.ngOnDestroy();
  }

  open() {
    super.open();
    const popover = window.document.querySelector('.popover');
    this._render.listen(popover, 'mouseover', () => {
      this.canClosePopover = false;
    });

    this._render.listen(popover, 'mouseout', () => {
      this.canClosePopover = true;
      setTimeout(() => { if (this.canClosePopover) { this.close(); } }, 0);
    });
  }

  close() {
    super.close();
  }

}

我有一个模块 SavedSearches 导入到 AdminModule 内部，该模块在 app.module.ts

内部进一步声明

当我在 SavedSearches 模块的模板中使用 StickyPopover 指令时，例如

<i class="fa fa-plus-circle" aria-hidden="true" appStickyPopover [popoverTitle]="additional" [autoClose]="true" data-placement="right"></i>

它给出了错误

can't bind to 'popoverTitle' since it isn't a known property of i

当我将指令移入 SavedSearches 模块并将其包含在 saved-searches.module.ts declaration 中时，它可以正常工作，没有任何错误。

但是我不能在另一个模块中使用它并且在其他模块中使用它会给出

StickyPopovoerDirective 是 2 个模块声明的一部分。 将它移到导入这两个模块的上层模块中。

Answer 1

该指令仅对AppModule可见，如果您想将其用于其他模块，您可以创建一个SharedModule。然后在声明和导出中添加StickyPopoverDirective。

@NgModule({
  declarations: [StickyPopoverDirective],
  exports: [StickyPopoverDirective]    
})
export class SharedModule { }

在此之后，您可以将SharedModule 导入另一个模块并在那里使用您的指令。