Create a view model and apply bindings: private void MainPage_Loaded(object sender, RoutedEventArgs e) { Model model = KO.NewObservable<Model>(); DataContext = KO.ApplyBindings(model, new { FullName = KO.Computed(() => model.FirstName + " " + model.LastName) }); } Where the model is simply: public class Model { public virtual string FirstName { get; set; } public virtual string LastName { get; set; } } This will data bind to all properties of the model plus the computed properties of the view model, as in: <TextBox Text="{Binding FirstName, Mode=TwoWay}"/> <TextBox Text="{Binding LastName, Mode=TwoWay}"/> <TextBlock Text="{Binding FullName}"/>