Question

Vistas

I'm writing an Angular component that has a property Mode(): string.

I would like to be able to set this property programmatically not in response to any event.

The problem is that in the absence of a browser event, a template binding {{Mode}} doesn't update.

Is there a way to trigger this change detection manually?

over 4 years ago · Santiago Trujillo

I used accepted answer reference and would like to put an example, since Angular 2 documentation is very very hard to read, I hope this is easier:

Import NgZone:

import { Component, NgZone } from '@angular/core';

Add it to your class constructor

constructor(public zone: NgZone, ...args){}

Run code with zone.run:

this.zone.run(() => this.donations = donations)

over 4 years ago · Santiago Trujillo Denunciar

I was able to update it with markForCheck()

Import ChangeDetectorRef

import { ChangeDetectorRef } from '@angular/core';

Inject and instantiate it

constructor(private ref: ChangeDetectorRef) { 
}

Finally mark change detection to take place

this.ref.markForCheck();

Here's an example where markForCheck() works and detectChanges() don't.

EDIT: This example doesn't portray the problem anymore :( I believe it might be running a newer Angular version where it's fixed.

(Press STOP/RUN to run it again)

over 4 years ago · Santiago Trujillo Denunciar

Responde la pregunta

Accepted Answer · 2022-05-18T13:19:54.004Z

Try one of these:

ApplicationRef.tick() - similar to AngularJS's $rootScope.$digest() -- i.e., check the full component tree
NgZone.run(callback) - similar to $rootScope.$apply(callback) -- i.e., evaluate the callback function inside the Angular zone. I think, but I'm not sure, that this ends up checking the full component tree after executing the callback function.
ChangeDetectorRef.detectChanges() - similar to $scope.$digest() -- i.e., check only this component and its children

You can inject ApplicationRef, NgZone, or ChangeDetectorRef into your component.