CODE EXAMPLE FOR TYPESCRIPT

ion select active by button

<ion-select [(ngModel)]="choices" multiple="true" #mySelect>
     <ion-option>Appliances</ion-option>
     ....
</ion-select>
<button ion-button (click)="openSelect()">Open</button>
....
@ViewChild('mySelect') selectRef: Select;
constructor(public navCtrl: NavController,public events: Events) {}
openSelect()
{
	this.selectRef.open();
}