Programatically check ion-radio inside two ngFor

Ionic Framework ionic-v3
1

I have to make a ion radio checked automatically based on the data in a list.

this is my code:

 <div *ngFor="let item of prelevementToDisplay">
            <ion-list radio-group *ngFor="let type of normePrelevementList; let i = index" [(ngModel)]="checkNorme">              
              <div *ngIf="type.name === item.normePrelevement">
                <ion-item>
                  <ion-label>{{type.name}} </ion-label>
                  <ion-radio [checked]="true"  value="{{type.name}}"></ion-radio>
                </ion-item>
              </div>
              <div *ngIf="type.name!== item.normePrelevement">
                <ion-item>
                  <ion-label>{{type.name}}</ion-label>
                  <ion-radio value="{{type.name}}"></ion-radio>
                </ion-item>
              </div>
</div>

nothing change. How can i resolve it ?

2

checked based on what exactly?

3

if the type.name === item.normePrelevement then the ion radio will be checked

4

but only one radio can be checked at once

checked="type.name === item.normePrelevement"

5

I romove the ngif. I try with your proposition. It seems to be rational but nothing changed: the ion radio is not checked.
i test the equality by using {{type.name === item.normePrelevement}}. It display true but the radio button is not checked

6

I see, but I dont know why it doesnt work this way

7

I figure out the problem.

<ion-list radio-group *ngFor="let type of normePrelevementList; let i = index" [(ngModel)]="checkNorme">       
<ion-item>
                  <ion-label>{{type.name}} </ion-label>
                  <ion-radio   [checked]="true" value="{{checkNorme}}"></ion-radio>
                </ion-item>.....

update

i undestrand know the strange behaviour. The value of ngmodel is null.
we need to set the checkNorme before we expose the dom

<ion-list radio-group *ngFor="let type of normePrelevementList; let i = index" [(ngModel)]="checkNorme">       
<ion-item>
                  <ion-label>{{type.name}} </ion-label>
                  <ion-radio  value="{{type.name}}"></ion-radio>
                </ion-item>.....