Support 2-way data binding (aka ng-model)

[tjvantoll]

One of the first things I wanted to do in my {N} + Angular 2 app was add a simple form, but I found it difficult since <TextField [text]="foo"> only uses one-way data binding, and <TextField [(ngModel)]="foo"> doesn’t work.

Can we some up with some way to incorporate Angular 2’s two-way data binding, ideally with the same [(ngModel)] syntax?

Thanks.

[hdeshev]

[(ngModel)]="foo" desugars to [ngModel]="foo" (ngModelChange)="foo = $event", and we don't provide *Change events for most properties.

We could make this work for NativeScript dependency properties by attaching property change events automatically in the renderer whenever we get a fooChange event attach request.

This one needs more research, as I'm afraid we could easily end up with circular change events or zone exceptions (aka "causing a change during change detection").

[nsndeck]

@tjvantoll

After a #36 it is now possible to do two-way binding via '[ngModel]`. A sample usage should look similar to the following:

<Label [text]='model.test'></Label>
<TextField #name [ngModel]='model.test'></TextField>

Where model is {N} Observable.