WPF - how to update textbox with currently selecteditem in listview? Using MVVM!

I'd be grateful if someone could give me some pointers on a very annoying problem I'm having - I'm going crazy trying to make this work as I'm sure there must be a simple solution but I can't see it!

As a result of the very helpful answers to my previous question posted on here, I'm attempting to use the MVVM approach in WPF.

I've got a listview in one page that binds to an ObservableCollection in the viewmodel & the listview's selected item is bound to a property called SelectedEntity in the viewmodel:

<Listview Name="listview" ItemsSource="{Binding Entities}" SelectedItem="{Binding SelectedEntity, Mode=TwoWay}">

In a different page I have a textbox bound to the Name property of SelectedEntity in the viewmodel:

<TextBlock Text="{Binding Path=SelectedEntity.Name}" />

The code in the viewmodel is:

Private Entity selectedEntity;
Public Entity SelectedEntity 
{ 
   get
   {
       return selectedEntity;
   }
   set
   {
       if (selectedEntity != value)
       {
           selectedEntity = value;
           RaisePropertyChanged("SelectedEntity"); 
       }
   }

RaisePropertyChanged is a method that implements INotify开发者_JS百科PropertyChanged.

What I want to do is have the textblock update when the currently selected item in the listview changes but it just won't? Am I missing something really obvious?

Thanks very much for any guidance you can give me!

I got this working using the MVVM Light Toolkit and have uploaded it here

It works because the ViewModelLocator holds a static reference to the ViewModel