Catel ViewToViewModel attribute - wpf

Question

Thank you so much for your help.
I'm trying to understand the ViewToViewModel attribute by getting a small example to work. I've go a couple of questions. My code is below.
Is the [ViewToViewModel] attribute supposed to be placed to be placed in the View, ViewModel or both?
If I try to use an attribute, MappingType, such as: [ViewToViewModel, MappingType = ...] MappingType gives me an error. Am I missing a "using" statement/Assembly Reference? Is there an example of syntax?
I'm able to get things to work the way I need, but I don't think that I'm getting the "ViewToViewModel" part to work properly. In the codebehind of the usercontrol, property changes are handled in HandleMyName(object e). Is ViewToViewModel supposed to do this?
Views:
MainWindow
UserControlView
ViewModels:
MainwindowViewModel
UserControlViewViewmodel
MainWindow
<catel:DataWindow x:Class="ViewToViewModelStudy.Views.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:catel="http://catel.codeplex.com"
xmlns:uc="clr-namespace:ViewToViewModelStudy.Views" >
<StackPanel x:Name="LayoutRoot">
<Label Content="{Binding Title}" />
<uc:UserControlView MyName="{Binding Title}" />
</StackPanel>
</catel:DataWindow>
.
UserControlView.xaml
<catel:UserControl x:Class="ViewToViewModelStudy.Views.UserControlView"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:catel="http://catel.codeplex.com">
<StackPanel>
<TextBlock>Innerview Model</TextBlock>
<TextBlock Text="{Binding MyName}"></TextBlock>
<TextBlock>Innerview Model</TextBlock>
</StackPanel>
</catel:UserControl>
UserControlView.xaml.cs
namespace ViewToViewModelStudy.Views
{
using Catel.Windows.Controls;
using Catel.MVVM.Views;
using System.Windows;
using System.Data;
public partial class UserControlView : UserControl
{
[ViewToViewModel]
public string MyName
{
get { return (string)GetValue(MyNameProperty); }
set { SetValue(MyNameProperty, value); }
}
public static readonly DependencyProperty MyNameProperty =
DependencyProperty.Register(
"MyName",
typeof(string),
typeof(UserControlView),
new FrameworkPropertyMetadata(null,
FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, new PropertyChangedCallback(OnMyName)));
static void OnMyName(DependencyObject obj, DependencyPropertyChangedEventArgs e)
{
UserControlView ic = (UserControlView)obj;
ic.HandleMyName(e.NewValue);
}
private void HandleMyName(object e)
{
ViewModels.UserControlViewModel vm = (ViewModels.UserControlViewModel)this.ViewModel;
if (vm != null)
{
vm.MyName = e.ToString(); // << Shouldn't this happen automagically?
}
}
public UserControlView()
{
InitializeComponent();
}
}
}
UserControlViewModel.cs
namespace ViewToViewModelStudy.ViewModels
{
using Catel.MVVM;
using Catel.Data;
using Catel.MVVM.Views;
using Catel.Windows.Controls;
public class UserControlViewModel : ViewModelBase
{
public UserControlViewModel()
{ }
public string MyName
{
get { return GetValue<string>(MyNameProperty); }
set { SetValue(MyNameProperty, value); }
}
public static readonly PropertyData MyNameProperty = RegisterProperty("MyName", typeof(string), null, (sender, e) => ((UserControlViewModel)sender).OnMyPropertyChanged());
private void OnMyPropertyChanged()
{
}
}
}

Answer 1

1) A ViewToViewModel should be located in the view (you don't want to pollute your VM with it).
2) The attribute should be used as [ViewToViewModel(MappingType = ...)]
3) The ViewToViewModel should handle the automatic mapping of property x on the view to property x on the view model. It will handle all change notifications automatically.