Accessing a property in a parent Component

There are different way:

• global service

  • see also
  • https://github.com/escardin/angular2-community-faq/blob/master/services.md#how-do-i-communicate-between-components-using-a-shared-service
  • Global Events in Angular 2
  • Plunker

• service shared by parent and injected to the child

  • similar to global service but listed in providers or viewProviders in the parent instead of boostrap(...) and only available to children of parent.

• parent injected to the child and accessed directly by the child

  • disadvantage: tight coupling

export class Profile implements OnInit {
constructor(@Host() parent: App) {
  parent.userStatus ...
}

• data-binding

export class Profile implements OnInit {
  @Input() userStatus:UserStatus;
  ...
}

<profile [userStatus]="userStatus">

I had the same problem but I solved it differently. I don't know if it's a good way of doing it, but it works great for what I need.

I used @Inject on the constructor of the child component, like this:

import { Component, OnInit, Inject } from '@angular/core';
import { ParentComponent } from '../views/parent/parent.component';

export class ChildComponent{
    constructor(@Inject(ParentComponent) private parent: ParentComponent){

    }

    someMethod(){
        this.parent.aPublicProperty = 2;
    }
}

This worked for me, you only need to declare the method or property you want to call as public.

In my case, the AppComponent handles the routing, and I'm using badges in the menu items to alert the user that new unread messages are available. So everytime a user reads a message, I want that counter to refresh, so I call the refresh method so that the number at the menu nav gets updated with the new value. This is probably not the best way but I like it for its simplicity.