title: Show/Hide Second DropDownSelect Based on First DropDownSelect in Ionic 3
body: <p>I'm very new in ionic, I'm trying to hide second dropdown based on selection of first dropdown.
  My first DropDown
  1.Bank
  2.Cash
  When i select Bank Second DropDown will be hidden and when select Cash then it will show second DropDown.</p>
  
  <p>.html file</p>
  
  <pre><code>&lt;ion-list no-lines&gt;
    &lt;ion-item&gt;
      &lt;ion-label&gt;Payment Mode&lt;/ion-label&gt;
      &lt;ion-select [(ngModel)]="paymentmode" (ionChange)="paymentModeChosen()"&gt;
        &lt;ion-option [value]="paymentmode" *ngFor="let paymentmode of 
           paymentmodes()"&gt;{{paymentmode}}&lt;/ion-option&gt;
       &lt;/ion-select&gt;
     &lt;/ion-item&gt;
  
    &lt;ion-item  *ngIf="paymentlocations"&gt;
      &lt;ion-label&gt;Payment Location&lt;/ion-label&gt;
      &lt;ion-select [(ngModel)]="paymentlocation" 
         (ionChange)="paymentLocationChosen()"&gt;
      &lt;ion-option  [value]="paymentlocation" *ngFor="let paymentlocation of 
        paymentlocations()"&gt;{{paymentlocation}}&lt;/ion-option&gt;
    &lt;/ion-select&gt;
  &lt;/ion-item&gt;
  &lt;/ion-list&gt;
  </code></pre>
  
  <p>.ts file</p>
  
  <pre><code>paymentmodes(): string[] {
  return [
    "Bank",
    "Cash"
  ]; }
   paymentmode: string = "Bank";
  
   paymentlocations(): string[] {
  return [
    "Ahmadabad",
    "Chennai",
    "Delhi",
    "Kolkata",
    "Mahad",
    "Mumbai",
    "Pune",
    "Roha",
    "Sahibabad"
  ];
  }
  
  paymentlocation: string = "Ahmadabad";
  
  constructor(public navCtrl: NavController, public navParams: NavParams) {}
  
  paymentModeChosen(): void {
    console.log(this.paymentmode);}
  
  paymentLocationChosen():void{
   console.log(this.paymentlocation);
  }}
  </code></pre>