<div *ngSwitchCase="'checkbox'"> <small>checkbox</small>
          <div *ngFor="let opt of question.options" >
               <label class="container-vertical"> {{opt.value}}
                   <input type="checkbox"
                          [formControlName]="question.key"
                          [name]="opt.name"
                          [value]="opt.key"
                          [checked]="opt.selectedOption"
                          (change)="onChangeValue($event)"
                          (blur)="onChangeValue($event)"
                          >

                   <span class="checkmark2"></span>
               </label>
          </div>
       </div>

handleCheckBoxChange (event: any) {

    console.log(".............. ",event);
    console.log("selected Value ", event.target.value);

    var target = event.target || event.srcElement || event.currentTarget;
    var idAttr = target.attributes.id;
    console.log("question id", idAttr);


  }

<div *ngSwitchCase="'checkbox'"> <small>checkbox</small>
              <div *ngFor="let opt of question.options" >
                   <label class="container-vertical"> {{opt.value}}
                       <input type="checkbox"
                              [formControlName]="question.key"
                              [name]="opt.name"
                              [value]="opt.key"
                              [(ngModel)]="opt.selectedOption"
                              (change)="onChangeValue()"
                              (blur)="onChangeValue()"
                              >

                       <span class="checkmark2"></span>
                   </label>
              </div>
           </div>

onChangeValue() {
  console.log(this.question);
  }