I have a public method that I exposed to window
. This method talks to a Component
and modifies a variable I am watching in my template. But when I change the value, the *ngIf()
does not get triggered.
app.component
constructor(private _public: PublicService,) {
window.angular = {methods: this._public};
}
PublicService
export class PublicService {
constructor(
private _viewManager: ViewManagerComponent,
) {}
CallMe(){
this._viewManager.renderView('page1')
}
}
LayoutManagerComponent
@Component({
selector: 'view-manager',
template: `<page *ngIf="view == 'page1'"></page>`
})
export class ViewManagerComponent {
//This is the variable being watched
view = "page";
renderView = function(type){
console.log(type)
this.view = type;
console.log(this.view)
};
}
So the idea is that when the view initially loads, the view is blank. Then when I type angular.methods.CallMe()
it modifies the view
variable to page1
which should then show the html for the Component. If I console renderView
function it is successfully getting called, just the view does not change.
----Update - Still not working -------
export class ViewManagerComponent {
constructor(private zone:NgZone,private cdRef:ChangeDetectorRef) {
}
view = "page";
@Output() renderView(type){
// type is 'page'
console.log(this.view)
this.zone.run(() => {
// type is 'page'
console.log(this.view)
this.view = type;
// type is 'page1'
console.log(this.view)
});
// type is 'page1'
console.log(this.view)
//cdRef errors:
//view-manager.component.ts:36 Uncaught TypeError: this.cdRef.detectChanges is not a function(…)
this.cdRef.detectChanges();
};
}
In this case Angular2 doesn't know that it needs to run change detection because the change is caused by code that runs outside Angulars zone.
Run change detection explicitely
contructor(private cdRef:ChangeDetectorRef) {}
someMethodCalledFromOutside() {
// code that changes properties in this component
this.cdRef.detectChanges();
}
Run the code that modifies the components properties inside Angulars zone explicitely
contructor(private zone:NgZone) {}
someMethodCalledFromOutside() {
this.zone.run(() => {
// code that changes properties in this component
});
}
The zone
method is a better fit when // code that changes properties in this component
not only changes properties of the current component, but also causes changes to other components (like this.router.navigate()
, call method references of methods of other components) because zone.run()
executes the code inside Angulars zone, and you don't need to explicitely take care of change detection in every component where a change might happen because of this call.
If you use function(...)
instead of () =>
it's likely you'll get unexpected behavior with this
in code inside the Angular component.
See also my answer to this similar question for more details Angular 2 - communication of typescript functions with external js libraries
update
export class ViewManagerComponent {
constructor(private zone:NgZone,private cdRef:ChangeDetectorRef) {
self = this;
}
view = "page";
@Output() renderView(type){
// type is 'page'
console.log(self.view)
self.zone.run(() => {
// type is 'page'
console.log(self.view)
self.view = type;
// type is 'page1'
console.log(self.view)
});
// type is 'page1'
console.log(self.view)
self.cdRef.detectChanges();
};
}