I think that it’s not supported. If you have a look at this DefaultValueAccessor directive (see https://github.com/angular/angular/blob/master/modules/angular2/src/common/forms/directives/default_value_accessor.ts#L23). You will see that the value used to update the bound element is $event.target.value.
This doesn’t apply in the case of inputs with type file since the file object can be reached $event.srcElement.files instead.
For more details, you can have a look at this plunkr: https://plnkr.co/edit/ozZqbxIorjQW15BrDFrg?p=info:
@Component({
selector: 'my-app',
template: `
<div>
<input type="file" (change)="onChange($event)"/>
</div>
`,
providers: [ UploadService ]
})
export class AppComponent {
onChange(event) {
var files = event.srcElement.files;
console.log(files);
}
}