Radio list: returning only one selected value

Ionic Framework ionic-v3
1

okay, this is what i want. sry for the stupid question!

          <ion-list radio-group [(ngModel)]="user">
              <ion-item *ngFor="let su of selectuser | async">
                  <ion-radio   [value]="su.name" ></ion-radio>
                  <ion-label > {{su.name}}  </ion-label>
              </ion-item>
          </ion-list>

I create a radio-list with this code:

         <ion-list radio-group>
              <ion-item *ngFor="let su of selectuser | async">
                  <ion-radio   [value]="su.name" detail-push (click)="saveSelect(su.name)"></ion-radio>
                  <ion-label > {{su.name}}  </ion-label>
              </ion-item>
          </ion-list>

Unbenannt

This works fine. If I click an item, the value returns.

Now I will modify this list/code by adding a button. Only by clicking the Button the value should returns.
Maybe like this not working code:

       <ion-list radio-group>
              <ion-item *ngFor="let su of selectuser | async">
                  <ion-radio   [value]="su.name" ></ion-radio>
                  <ion-label > {{su.name}}  </ion-label>
              </ion-item>
          </ion-list>

        

          <button ion-button (click)="saveSelect(user)">Send</button>

button

Some Ideas?