Angular中的全局事件

Angular中没有等价的$scope.emit()或$scope.broadcast()吗?

我知道EventEmitter功能，但据我所知，它只会向父HTML元素发出一个事件。

如果我需要在fx和。还是DOM根组件和嵌套了几层的元素之间?

当前回答

不要使用EventEmitter来进行服务通信。

你应该使用Observable类型之一。我个人喜欢BehaviorSubject。

简单的例子:

你可以传递初始状态，这里我传递null

let subject = new BehaviorSubject(null);

当你想要更新主题时

next (myObject)科目。

观察任何服务或组件，并在其获得新的更新时采取行动。

subject.subscribe (this.YOURMETHOD);

这里有更多信息。

2017-07-24 03:31:36

其他回答

我们实现了一个ngModelChange可观察指令，它通过你在自己的组件中实例化的事件发射器发送所有模型更改。您只需将事件发射器绑定到该指令。

参见:https://github.com/atomicbits/angular2-modelchangeobservable

在html中，绑定你的事件发射器(本例中为countryChanged):

<input [(ngModel)]="country.name"
       [modelChangeObservable]="countryChanged" 
       placeholder="Country"
       name="country" id="country"></input>

在你的typescript组件中，对EventEmitter执行一些异步操作:

import ...
import {ModelChangeObservable} from './model-change-observable.directive'


@Component({
    selector: 'my-component',
    directives: [ModelChangeObservable],
    providers: [],
    templateUrl: 'my-component.html'
})

export class MyComponent {

    @Input()
    country: Country

    selectedCountries:Country[]
    countries:Country[] = <Country[]>[]
    countryChanged:EventEmitter<string> = new EventEmitter<string>()


    constructor() {

        this.countryChanged
            .filter((text:string) => text.length > 2)
            .debounceTime(300)
            .subscribe((countryName:string) => {
                let query = new RegExp(countryName, 'ig')
                this.selectedCountries = this.countries.filter((country:Country) => {
                    return query.test(country.name)
                })
            })
    }
}

2016-07-28 11:42:45

下面的代码是Angular 2中使用共享服务来处理事件的$scope.emit()或$scope.broadcast()的替换示例。

import {Injectable} from 'angular2/core';
import * as Rx from 'rxjs/Rx';

@Injectable()
export class EventsService {
    constructor() {
        this.listeners = {};
        this.eventsSubject = new Rx.Subject();

        this.events = Rx.Observable.from(this.eventsSubject);

        this.events.subscribe(
            ({name, args}) => {
                if (this.listeners[name]) {
                    for (let listener of this.listeners[name]) {
                        listener(...args);
                    }
                }
            });
    }

    on(name, listener) {
        if (!this.listeners[name]) {
            this.listeners[name] = [];
        }

        this.listeners[name].push(listener);
    }

    off(name, listener) {
        this.listeners[name] = this.listeners[name].filter(x => x != listener);
    }

    broadcast(name, ...args) {
        this.eventsSubject.next({
            name,
            args
        });
    }
}

使用示例:

广播:

function handleHttpError(error) {
    this.eventsService.broadcast('http-error', error);
    return ( Rx.Observable.throw(error) );
}

听众:

import {Inject, Injectable} from "angular2/core";
import {EventsService}      from './events.service';

@Injectable()
export class HttpErrorHandler {
    constructor(eventsService) {
        this.eventsService = eventsService;
    }

    static get parameters() {
        return [new Inject(EventsService)];
    }

    init() {
        this.eventsService.on('http-error', function(error) {
            console.group("HttpErrorHandler");
            console.log(error.status, "status code detected.");
            console.dir(error);
            console.groupEnd();
        });
    }
}

它可以支持多个参数:

this.eventsService.broadcast('something', "Am I a?", "Should be b", "C?");

this.eventsService.on('something', function (a, b, c) {
   console.log(a, b, c);
});

2016-03-29 00:06:22

我最喜欢的方法是在我的服务中使用行为主题或事件发射器(几乎相同)来控制我的所有子组件。

使用angular cli，运行ng gs来创建一个新的服务，然后使用BehaviorSubject或EventEmitter

export Class myService {
#all the stuff that must exist

myString: string[] = [];
contactChange : BehaviorSubject<string[]> = new BehaviorSubject(this.myString);

   getContacts(newContacts) {
     // get your data from a webservices & when you done simply next the value 
    this.contactChange.next(newContacts);
   }
}

当您这样做时，作为提供者使用您的服务的每个组件都将知道更改。只需订阅结果，就像你用eventEmitter;)

export Class myComp {
#all the stuff that exists like @Component + constructor using (private myService: myService)

this.myService.contactChange.subscribe((contacts) => {
     this.contactList += contacts; //run everytime next is called
  }
}

2017-07-19 14:18:56

这是我的版本:

export interface IEventListenr extends OnDestroy{
    ngOnDestroy(): void
}

@Injectable()
export class EventManagerService {


    private listeners = {};
    private subject = new EventEmitter();
    private eventObserver = this.subject.asObservable();


    constructor() {

        this.eventObserver.subscribe(({name,args})=>{



             if(this.listeners[name])
             {
                 for(let listener of this.listeners[name])
                 {
                     listener.callback(args);
                 }
             }
        })

    }

    public registerEvent(eventName:string,eventListener:IEventListenr,callback:any)
    {

        if(!this.listeners[eventName])
             this.listeners[eventName] = [];

         let eventExist = false;
         for(let listener of this.listeners[eventName])
         {

             if(listener.eventListener.constructor.name==eventListener.constructor.name)
             {
                 eventExist = true;
                 break;
             }
         }

        if(!eventExist)
        {
             this.listeners[eventName].push({eventListener,callback});
        }
    }

    public unregisterEvent(eventName:string,eventListener:IEventListenr)
    {

        if(this.listeners[eventName])
        {
            for(let i = 0; i<this.listeners[eventName].length;i++)
            {

                if(this.listeners[eventName][i].eventListener.constructor.name==eventListener.constructor.name)
                {
                    this.listeners[eventName].splice(i, 1);
                    break;
                }
            }
        }


    }


    emit(name:string,...args:any[])
    {
        this.subject.next({name,args});
    }
}

use:

export class <YOURCOMPONENT> implements IEventListener{

  constructor(private eventManager: EventManagerService) {


    this.eventManager.registerEvent('EVENT_NAME',this,(args:any)=>{
       ....
    })


  }

  ngOnDestroy(): void {
    this.eventManager.unregisterEvent('closeModal',this)
  }

}

发出:

 this.eventManager.emit("EVENT_NAME");

2017-01-26 10:55:53