Ion-select select default value not working

Ionic Framework ionic-v3
1

I have ion-select with that have many options and I have when the view is ready to select one default value depending on CurrentNumber. i have this code:

<ion-select formControlName="Level">
          <ion-option [value]="level.id" *ngFor="let level of levels" [attr.selected]="(level.levelNumber == currentLevel)? true : null">
             {{level.name}}
          </ion-option>
</ion-select>

this.currentLevel = 1;
the data comes from the server like that :

data = [
 {
  levelNumber : 1,
  name:'abcd'
 },
 {
levelNumber:2,
name:'efg'
 }
]
2

The selected attribute is ignored if the ion-select is bound. You must assign to your backing FormControl instead to set the initial selection.

3

yes i put the value in the formControl when the values ready.
this.formName.controls.fieldName.setValue(value);