angular2 how to call method of object - forms

Question

I have an model in which I have a method is valid
export class ModelClass{
id: number;
text : String,
isValid() : boolean {
return true;
}
}
a second model
export class Rows{
editable: boolean;
modelClass: ModelClass;
}
how to call it in html ???
<table border="1p;">
<tbody >
<tr *ngFor="let link of modelClassRows">
<td>
<div>toto {{link.applicationLink.isValid()}}</div>
</td>
</tr>
</tbody>
</table>
a part of my component where object are initialized
export class ApplicationLinkListComponent implements OnInit {
modelClassRows: Rows[] = new Array<Rows>();
constructor() {
}
ngOnInit() {
// fill modelClassRows
.....
}

Answer 1

You need to instantiate the ModelClass class this way:
let row = new Rows();
row.modelClass = new ModelClass();
row.modelClass.id = 'some id';
row.modelClass.title = 'some title';
modelClassRows.push(row);
If you instantiate it literally and cast it to the type, you won't be able to use the method.
For example:
let row = new Rows();
row.modelClass = <ModelClass>{
id: 'some id',
title: 'some title'
};
modelClassRows.push(row);