Question

I’m writting a form in WPF/c# with the MVVM pattern and trying to share data with a user control. (Well, the User Controls View Model)

I either need to:

1. Create a View model in the parents and bind it to the User Control
2. Bind certain classes with the View Model in the Xaml
3. Be told that User Controls arn’t the way to go with MVVM and be pushed in the correct direction. (I’ve seen data templates but they didn’t seem ideal)

The usercontrol is only being used to make large forms more manageable so I’m not sure if this is the way to go with MVVM, it’s just how I would of done it in the past.

I would like to pass a class the VM contruct in the Xaml.

<TabItem Header="Applicants">
     <Views:ApplicantTabView>
         <UserControl.DataContext>
             <ViewModels:ApplicantTabViewModel Client="{Binding Client} />
         </UserControl.DataContext>
     </Views:ApplicantTabView>
 </TabItem>

public ClientComp Client
    {
        get { return (ClientComp)GetValue(ClientProperty); }
        set { SetValue(ClientProperty, value); }
    }

public static readonly DependencyProperty ClientProperty = DependencyProperty.Register("Client", typeof(ClientComp),
                                                                           typeof(ApplicantTabViewModel),
                                                                                       new FrameworkPropertyMetadata
                                                                                           (null));

But I can’t seem to get a dependancy property to accept non static content.

This has been an issue for me for a while but assumed I’d find out but have failed so here I am here.

Thanks in advance,
Oli

Answer 1

I answered a similar question as yours recently: passing a gridview selected item value to a different ViewModel of different Usercontrol

Essentially setting up a dependency property which allows data from your parent view to persist to your child user control. Abstracting your view into specific user controls and hooking them using dependency properties along with the MVVM pattern is actually quite powerful and recommended for Silverlight/WPF development, especially when unit testing comes into play. Let me know if you’d like any more clarification, hope this helps.