CODEWITHSUNDEEP
angularangular2-templatengfor
Rafael
Rafael

Reputation: 5149

Updating ngFor when Input value changes

I'm trying to get an better understanding of Angular 2. I am receiving a list of people from endpoint and periodically the list changes. People Component:

@Component({
   selector: 'people-display',
   template: <ol class="people-list">
                <li *ngFor="let person of people">
                   <attendees [people]="peopleValue"></attendees>
                </li>
             </ol>
})
export class PeopleComponent implements OnChanges {
   @Input() people: string[];
}

Attendees Component:

@Component({
  selector: 'attendees',
  templateUrl: '<span>{{attendees}}</span>',
})
export class AttendeesComponent implements OnInit {
  constructor() { }
  ngOnInit() {}
}

I've looked for a way to change automatically update my template whenever the value of input changes. I have yet to find a way of doing this. I've thought about doing a setTimout, but there has to be more efficient way. Can someone assist me or point me in the right direction? I need the ngFor to update dynamically.

Upvotes: 0

Views: 1845

Answers (3)

Suneet Bansal
Suneet Bansal

Reputation: 2702

For your purpose Angular provides you two way binding where any further changes to the model gets refelected to the template automatically and vice-versa.

Example:

List Component

@Component({
    selector: 'my-comp',
    template: `<ul>
                    <li *ngFor="let item of people">{{item}}</li>
               </ul>`
})

export class MyComp {
    @Input() people: string[];
}

Usage

@Component({
    selector: 'main-comp',
    template: '<my-comp [people]="list"></my-comp>'
})


export class MainComp {
    private list: string[];

    ngOnInit() {
        this.list= ['male', 'female'];
    }
}

Upvotes: 0

Sajeetharan
Sajeetharan

Reputation: 222582

You do not have to do anything manually inorder to track changes, angular2 framework automatically does that , make sure you pass the people as a input to your child component,

Assuming mycomponent is your child component and people is the input

<mycomponent [people]="peopleValue" .... ></mycomponent>

Upvotes: 0

Amr Eladawy
Amr Eladawy

Reputation: 4358

The question is how do you pass people to your component.

Assuming that your component is my-people then you should pass people as following

<my-people [people]="peopleValue" .... ></my-people>

Upvotes: 2

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