Want a scrollabe list inside content but scrolling list should not scroll entire content

Ionic Framework ionic-v3
1

Hi guys, I tried using ion-scroll first as following,

<ion-content>
  <div>
    some conent
  </div>

  <ion-scroll scrollY="true">
    <ion-list>
      <ion-item *ngFor=...></ion-item>
    </ion-list>
  </ion-scroll>
</ion-content>

but ion-scroll not worked, I guessed it failed to work because the list was dynamically created, so the ion-scroll height was 0 at the beginning.

The list height always expands content, how could I make the list only scroll itself? thanks