0

我定义了一个警报指令，如下所示：

import { Component } from 'angular2/core';
import { CORE_DIRECTIVES } from 'angular2/common';
import { Alert } from 'ng2-bootstrap/ng2-bootstrap';

@Component({
  selector: 'alert_directive',
  templateUrl: './shared/directives/alert/alert.html',
  directives: [Alert, CORE_DIRECTIVES]
})
export class AlertDirective {
  alerts:Array<Object> = [ ];

  closeAlert(i:number) {
    this.alerts.splice(i, 1);
  }

  addAlert(message: string, style: string) {
    this.alerts.push({msg: message, type: style, closable: true});
    console.log(this.alerts);
  }
}

然后，我定义了app包含此指令的组件：

import {AlertDirective} from '../../shared/directives/alert/alert';
...
@Component({
  selector: 'app',
  templateUrl: './app/components/app.html',
  styleUrls: ['./app/components/app.css'],
  providers: [UserService, HTTP_PROVIDERS],
  encapsulation: ViewEncapsulation.None,
  directives: [ROUTER_DIRECTIVES, AlertDirective]
})
...

这一切都有效，并且该指令显示在与我的app.html文件相关的 DOM 中。

该app.html文件包含一些全局 html（导航栏、页脚、alert_directive）。我想alert_directive成为一个单身人士，我可以更改alerts数组以显示来自任何视图的警报消息，而无需将指令添加到每个视图。

所以，在另一个sign in组件中：

import {Component, ViewEncapsulation} from 'angular2/core';
import {AlertDirective} from '../../shared/directives/alert/alert';
@Component({
  selector: 'sign_in',
  templateUrl: './sign_in/components/sign_in.html',
  styleUrls: ['./sign_in/components/sign_in.css'],
  encapsulation: ViewEncapsulation.Emulated
})
export class SignInCmp {
  alertDirective: AlertDirective;
  constructor(alertDirective: AlertDirective) {
    this.alertDirective = alertDirective;
  }

  showAlert() {
    this.alertDirective.addAlert('test', 'warning');
  }
}

这里的问题是我newing创建了一个新实例AlertDirective，因此我的方法是添加到我的新实例的数组中，而不是在我的组件addAlert中定义的现有实例。app

如何将指令创建为单例并将单个实例注入每个视图，然后我可以在该单例上调用任何方法并影响每个注入的实例？

4

1 回答 1

3

创建一个共享服务（仅在 中注册bootstrap()）并使用它在组件之间进行通信，以及如何在 Angular2AlertDirective中的组件之间共享数据？ 该服务还可以包含一个所有参与者都可以订阅传递的消息。EventEmitter

@Injectable()
export class AlertService {
  command: EventEmitter = new EventEmitter();
}

@Component({
  selector: 'alert_directive',
  templateUrl: './shared/directives/alert/alert.html',
  directives: [Alert, CORE_DIRECTIVES]
})
export class AlertDirective {
  constructor(private alertService: AlertService) {
    alertService.commands.subscribe((command) => { doSomething();}
  }
  alerts:Array<Object> = [ ];

  closeAlert(i:number) {
    this.alerts.splice(i, 1);
  }

  addAlert(message: string, style: string) {
    this.alerts.push({msg: message, type: style, closable: true});
    console.log(this.alerts);
  }
}

@Component({
  selector: 'sign_in',
  templateUrl: './sign_in/components/sign_in.html',
  styleUrls: ['./sign_in/components/sign_in.css'],
  encapsulation: ViewEncapsulation.Emulated
})
export class SignInCmp {
  alertDirective: AlertDirective;
  constructor(alertService: AlertService) {
    this.alertService = alertService;
  }

  showAlert() {
    this.sharedService.command.next({text: 'test', title: 'warning'});
  }
}

bootstrap(AppComponent, [/* other providers */, AlertService]);
于 2016-02-03T04:36:23.153 回答