public static ISubscription bind <A, Control>(
this RxList <A> list, int max, string maxName,
Fn <int, Control> getControl, Act <Control, A> onChange
) where Control : dfControl
{
return(list.bind(max, maxName, (i, observable) => {
var control = getControl(i);
return observable.subscribe(opt => {
control.SetIsActive(opt.isDefined);
opt.each(v => onChange(control, v));
});
}));
}