angular2-select cannot set the default value

Question

Trying to use ( in angular4 ) this angular2 select component, angular2-select. The docs is here.

The example given is working with simple variable.

SelectedValue = '3';

Data binding is working fine. ( I suppose )

But in my case, I am binding to a property of an object. Something like:

[(ngModel)]="eventData.event.code"

So if I want to set a default value in ngInit, it doesn't work. this.eventData.event.code = "abc";

Beside setting default value, data binding using ngModel is working fine.

<ng-select 
    name="eventDataCode" 
    id="eventDataCode" 
    [options]="codeList" 
    placeholder="" 
    [(ngModel)]="eventData.event.code" required ></ng-select>

ngOnInit() {

    this.eventData = new EventData;
    this.eventData.event.code = "abc";
    console.log(this.eventData.event);// code:undefined
    console.log(this.eventData.event.code);// code:abc
}