I´m fairly new to Angular2 and I have a little problem:
In my Login-Component-HTML, I have two checkboxes, which I want to bind in two way data-binding to the Login-Component-TypeScript.
This is the HTML:
<div class="checkbox">
<label>
<input #saveUsername [(ngModel)]="saveUsername.selected" type="checkbox" data-toggle="toggle">Save username
</label>
</div>
And this is the Component.ts:
import { Component, OnInit } from '@angular/core';
import { Router } from '@angular/router';
import { Variables } from '../../services/variables';
@Component({
selector: 'login',
moduleId: module.id,
templateUrl: 'login.component.html',
styleUrls: ['login.component.css']
})
export class LoginComponent implements OnInit {
private saveUsername: boolean = true;
private autoLogin: boolean = true;
constructor(private router: Router, private variables: Variables) { }
ngOnInit() {
this.loginValid = false;
// Get user name from local storage if you want to save
if (window.localStorage.getItem("username") === null) {
this.saveUsername = true;
this.autoLogin = true;
console.log(this.saveUsername, this.autoLogin);
} else {
console.log("init", window.localStorage.getItem("username"));
}
}
login(username: string, password: string, saveUsername: boolean, autoLogin: boolean) {
this.variables.setUsername(username);
this.variables.setPassword(password);
this.variables.setIsLoggedIn(true);
console.log(saveUsername, autoLogin);
//this.router.navigate(['dashboard']);
}
If I click an checkbox, I get the correct value in the controller (component).
But if I change the value of for example saveUsername
in the component, the checkbox didn't "get" the new value.
So I can´t manipulate the checkbox from the Component (like I want to do in the ngOnInit
in the component.
Thanks for your help!
This question is related to
html
angular
typescript
checkbox
data-binding
To get checkbox work you should follow all these steps:
FormsModule
in your moduleform
tagyour input should be like this:
<input name="mpf" type="checkbox" [(ngModel)]="value" />
Note: do not forget to put name in your input.
When using <abc [(bar)]="foo"/>
syntax on angular.
This translates to:
<abc [bar]="foo" (barChange)="foo = $event" />
Which means your component should have:
@Input() bar;
@Output() barChange = new EventEmitter();
In Angular p-checkbox,
Use all attributes of p-checkbox
<p-checkbox name="checkbox" value="isAC"
label="All Colors" [(ngModel)]="selectedAllColors"
[ngModelOptions]="{standalone: true}" id="al"
binary="true">
</p-checkbox>
And more importantly, don't forget to include [ngModelOptions]="{standalone: true}
as well as it SAVED MY DAY.
In any situation, if you have to bind a value with a checkbox which is not boolean then you can try the below options
In the Html file:
<div class="checkbox">
<label for="favorite-animal">Without boolean Value</label>
<input type="checkbox" value="" [checked]="ischeckedWithOutBoolean == 'Y'"
(change)="ischeckedWithOutBoolean = $event.target.checked ? 'Y': 'N'">
</div>
in the componentischeckedWithOutBoolean: any = 'Y';
See in the stackblitz https://stackblitz.com/edit/angular-5szclb?embed=1&file=src/app/app.component.html
I prefer something more explicit:
component.html
<input #saveUserNameCheckBox
id="saveUserNameCheckBox"
type="checkbox"
[checked]="saveUsername"
(change)="onSaveUsernameChanged(saveUserNameCheckBox.checked)" />
component.ts
public saveUsername:boolean;
public onSaveUsernameChanged(value:boolean){
this.saveUsername = value;
}
I'm working with Angular5 and I had to add the "name" attribute to get the binding to work... The "id" is not required for binding.
<input type="checkbox" id="rememberMe" name="rememberMe" [(ngModel)]="rememberMe">
You must add name="selected"
attribute to input
element.
For example:
<div class="checkbox">
<label>
<input name="selected" [(ngModel)]="saveUsername.selected" type="checkbox">Save username
</label>
</div>
I know it may be repeated answer but for any one want to load list of checkboxes with selectall checkbox into angular form i follow this example: Select all/deselect all checkbox using angular 2+
it work fine but just need to add
[ngModelOptions]="{standalone: true}"
the final HTML should be like this:
<ul>
<li><input type="checkbox" [(ngModel)]="selectedAll" (change)="selectAll();"/></li>
<li *ngFor="let n of names">
<input type="checkbox" [(ngModel)]="n.selected" (change)="checkIfAllSelected();">{{n.name}}
</li>
</ul>
TypeScript
selectAll() {
for (var i = 0; i < this.names.length; i++) {
this.names[i].selected = this.selectedAll;
}
}
checkIfAllSelected() {
this.selectedAll = this.names.every(function(item:any) {
return item.selected == true;
})
}
hope this help thnx
I have done a custom component tried two way binding
Mycomponent:
<input type="checkbox" [(ngModel)]="model" >
_model: boolean;
@Output() checked: EventEmitter<boolean> = new EventEmitter<boolean>();
@Input('checked')
set model(checked: boolean) {
this._model = checked;
this.checked.emit(this._model);
console.log('@Input(setmodel'+checked);
}
get model() {
return this._model;
}
strange thing is this works
<mycheckbox [checked]="isChecked" (checked)="isChecked = $event">
while this wont
<mycheckbox [(checked)]="isChecked">
A workaround to achieve the same specially if you want to use checkbox with for loop is to store the state of the checkbox inside an array and change it based on the index of the *ngFor
loop. This way you can change the state of the checkbox in your component.
app.component.html
<div *ngFor="let item of items; index as i">
<input type="checkbox" [checked]="category[i]" (change)="checkChange(i)">
{{item.name}}
</div>
app.component.ts
items = [
{'name':'salad'},
{'name':'juice'},
{'name':'dessert'},
{'name':'combo'}
];
category= []
checkChange(i){
if (this.category[i]){
this.category[i] = !this.category[i];
}
else{
this.category[i] = true;
}
}
Unfortunately solution provided by @hakani is not two-way binding. It just handles One-way changing model from UI/FrontEnd part.
Instead the simple:
<input [(ngModel)]="checkboxFlag" type="checkbox"/>
will do two-way binding for checkbox.
Afterwards, when Model checkboxFlag is changed from Backend or UI part - voila, checkboxFlag stores actual checkbox state.
To be sure I've prepared Plunker code to present the result : https://plnkr.co/edit/OdEAPWRoqaj0T6Yp0Mfk
Just to complete this answer you should include the import { FormsModule } from '@angular/forms'
into app.module.ts
and add to imports array i.e
import { FormsModule } from '@angular/forms';
[...]
@NgModule({
imports: [
[...]
FormsModule
],
[...]
})
Angular: "9.0.0"
Angular CLI: 9.0.1
Node: 13.10.1
OS: linux x64
.html file
<input [(ngModel)]="userConsent" id="userConsent" required type="checkbox"/> " I Accept"
.ts file
userConsent: boolean = false;
You can just use something like this to have two way data binding:
<input type="checkbox" [checked]="model.property" (change)="model.property = !model.consent_obtained_ind">
My angular directive like angularjs (ng-true-value ng-false-value)
@Directive({
selector: 'input[type=checkbox][checkModel]'
})
export class checkboxDirective {
@Input() checkModel:any;
@Input() trueValue:any;
@Input() falseValue:any;
@Output() checkModelChange = new EventEmitter<any>();
constructor(private el: ElementRef) { }
ngOnInit() {
this.el.nativeElement.checked = this.checkModel==this.trueValue;
}
@HostListener('change', ['$event']) onChange(event:any) {
this.checkModel = event.target.checked ? this.trueValue : this.falseValue;
this.checkModelChange.emit(this.checkModel);
}
}
html
<input type="checkbox" [(checkModel)]="check" [trueValue]="1" [falseValue]="0">
Source: Stackoverflow.com