Bug: NG0100: ExpressionChangedAfterItHasBeenCheckedError

[AlexanderBelkin]

I used the default example and when I removed *ngFor.
as :

<mat-carousel
....params
>
  <mat-carousel-slide > first slide  </mat-carousel-slide>

  <mat-carousel-slide> second slide  </mat-carousel-slide>
</mat-carousel>

I got an error :

ERROR Error: NG0100: ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked. Previous value: 'undefined'. Current value: '[object Object]'.. Find more at https://angular.io/errors/NG0100

my goal was to make a certain number of slides without using a loop.

Can I solve this error locally?

Thank for your help

[tagazok]

Same error here while creating slides directly from HTML and not from a for loop.

Complete trace below

core.js:6479 ERROR Error: NG0100: ExpressionChangedAfterItHasBeenCheckedError: Expression has changed after it was checked. Previous value: 'undefined'. Current value: '[object Object]'.. Find more at https://angular.io/errors/NG0100
    at throwErrorIfNoChangesMode (core.js:6776)
    at bindingUpdated (core.js:12988)
    at Module.ɵɵproperty (core.js:14783)
    at MatCarouselComponent_li_4_Template (ngbmodule-material-carousel.js:56)
    at executeTemplate (core.js:9598)
    at refreshView (core.js:9464)
    at refreshEmbeddedViews (core.js:10589)
    at refreshView (core.js:9488)
    at refreshComponent (core.js:10635)
    at refreshChildComponents (core.js:9261)

[mac1253]

I too had the issue and couldnt resolve this. Any updates on this?
EDIT: I wasn't able to get it working right from the docs but I hacked the demo apart but had to fit an image tag within the slide tag and just fit it to what it would normally be.

[Babelfish112]

Any updates? Same error here - it's unfortunately preventing me from using this module at all.

[notman]

This may be a result of implementation. Without seeing all the code, it's difficult to know, but based on the error messaging, it appears you are setting the an array, for the ngFor, but not initially defining that array.
For example, if you are doing the following in your component:

public slides: Slide[];

public ngOnInit():{
 loadSlides().subscribe((loadedSlides: Slide[]) => this.slides = loadedSlides);
} 

You should instead do this:

public slides: Slide[] = [];

public ngOnInit():{
 loadSlides().subscribe((loadedSlides: Slide[]) => this.slides = loadedSlides); 
//or
 loadSlides().subscribe((loadedSlides: Slide[]) => this.slides = this.slides.concat(loadedSlides)); 
} 

Or add a changeDetectorRef and set 'detectChanges' in your ngOnInit. This is another way to get angular to process the current value, before you change it to an array. The better practice would be to always initialize your properties though.

Again, this is all based on assumptions, without seeing the actual implementation. These are solutions that typically resolve that 'expression changed' error. We use async pipes, which offer a better way of handling this