Angular 2 - ng-bootstrap dropdown with formControlName

Unfortunately, ng-bootstrap dropdown can't be used as a form control out-of-the-box.

But it's possible to create your own component that will be used as a form control. To do it, you need to implement ControlValueAccessor interface. You can read more in this article: https://blog.thoughtram.io/angular/2016/07/27/custom-form-controls-in-angular-2.html