Angular 2: Get Values of Multiple Checked Checkbox

Question

My problem is really simple: I have a list of checkboxes like this:

<div class="form-group">
    <label for="options">Options :</label>
    <label *ngFor="#option of options" class="form-control">
        <input type="checkbox" name="options" value="option" /> {{option}}
    </label>
</div>

And I would like to send an array of the selected options, something like: [option1, option5, option8] if options 1, 5 and 8 are selected. This array is part of a JSON that I would like to send via an HTTP PUT request.

Thanks for your help!

Answer 1

Here's a simple way using ngModel (final Angular 2)

<!-- my.component.html -->

<div class="form-group">
    <label for="options">Options:</label>
    <div *ngFor="let option of options">
        <label>
            <input type="checkbox"
                   name="options"
                   value="{{option.value}}"
                   [(ngModel)]="option.checked"/>
            {{option.name}}
        </label>
    </div>
</div>

---

// my.component.ts

@Component({ moduleId:module.id, templateUrl:'my.component.html'})

export class MyComponent {
  options = [
    {name:'OptionA', value:'1', checked:true},
    {name:'OptionB', value:'2', checked:false},
    {name:'OptionC', value:'3', checked:true}
  ]

  get selectedOptions() { // right now: ['1','3']
    return this.options
              .filter(opt => opt.checked)
              .map(opt => opt.value)
  }
}

Answer 2

I just faced this issue, and decided to make everything work with as less variables as i can, to keep workspace clean. Here is example of my code

<input type="checkbox" (change)="changeModel($event, modelArr, option.value)" [checked]="modelArr.includes(option.value)" />

Method, which called on change is pushing value in model, or removing it.

public changeModel(ev, list, val) {
  if (ev.target.checked) {
    list.push(val);
  } else {
    let i = list.indexOf(val);
    list.splice(i, 1);
  }
}

Answer 3

create a list like :-

this.xyzlist = [
  {
    id: 1,
    value: 'option1'
  },
  {
    id: 2,
    value: 'option2'
  }
];

Html :-

<div class="checkbox" *ngFor="let list of xyzlist">
            <label>
              <input formControlName="interestSectors" type="checkbox" value="{{list.id}}" (change)="onCheckboxChange(list,$event)">{{list.value}}</label>
          </div>

then in it's component ts :-

onCheckboxChange(option, event) {
     if(event.target.checked) {
       this.checkedList.push(option.id);
     } else {
     for(var i=0 ; i < this.xyzlist.length; i++) {
       if(this.checkedList[i] == option.id) {
         this.checkedList.splice(i,1);
      }
    }
  }
  console.log(this.checkedList);
}

Answer 4

<input type="checkbox" name="options" value="option" (change)="updateChecked(option, $event)" /> 

export class MyComponent {
  checked: boolean[] = [];
  updateChecked(option, event) {
    this.checked[option]=event; // or `event.target.value` not sure what this event looks like
  }
}

Answer 5

1. I have just simplified little bit for those whose are using list of value Object. XYZ.Comonent.html

   <div class="form-group">
           <label for="options">Options :</label>
           <div *ngFor="let option of xyzlist">
               <label>
                   <input type="checkbox"
                          name="options"
                          value="{{option.Id}}"
   
                          (change)="onClicked(option, $event)"/>
                   {{option.Id}}-- {{option.checked}}
               </label>
           </div>
           <button type="submit">Submit</button>
       </div> 
   

   ** XYZ.Component.ts**.

2. create a list -- xyzlist.

3. assign values, I am passing values from Java in this list.
4. Values are Int-Id, boolean -checked (Can Pass in Component.ts).

5. Now to get value in Componenet.ts.

   xyzlist;//Just created a list
   onClicked(option, event) {
       console.log("event  " + this.xyzlist.length);
       console.log("event  checked" + event.target.checked);
       console.log("event  checked" + event.target.value);
       for (var i = 0; i < this.xyzlist.length; i++) {
           console.log("test --- " + this.xyzlist[i].Id;
           if (this.xyzlist[i].Id == event.target.value) {
               this.xyzlist[i].checked = event.target.checked;
           }
           console.log("after update of checkbox" + this.xyzlist[i].checked);
   
       }
   

Answer 6

I have encountered the same problem and now I have an answer I like more (may be you too). I have bounded each checkbox to an array index.

First I defined an Object like this:

SelectionStatusOfMutants: any = {};

Then the checkboxes are like this:

<input *ngFor="let Mutant of Mutants" type="checkbox"
[(ngModel)]="SelectionStatusOfMutants[Mutant.Id]" [value]="Mutant.Id" />

As you know objects in JS are arrays with arbitrary indices. So the result are being fetched so simple:

Count selected ones like this:

let count = 0;
    Object.keys(SelectionStatusOfMutants).forEach((item, index) => {
        if (SelectionStatusOfMutants[item])
            count++;
    });

And similar to that fetch selected ones like this:

let selecteds = Object.keys(SelectionStatusOfMutants).filter((item, index) => {
        return SelectionStatusOfMutants[item];
    });

You see?! Very simple very beautiful. TG.