How to determine the closed documentwindow in mvvm?

Hi,

according to your mvvm samples I've created a test application using the docking control. The application contains a few viewmodels that inherits from a class called DocumentWindowViewModelBase (not of further interest).

The application also contains a DeferrableObserableCollection called _documentWindows and a property GetDocumentWindows, that is the binding source for the DockSite:

Private _documentWindows As New DeferrableObservableCollection(Of DocumentWindowViewModelBase)()

Public ReadOnly Property GetDocumentWindows() As IList(Of DocumentWindowViewModelBase)
    Get
        Return _documentWindows
    End Get
End Property

<docking:DockSite x:Name="dockSite"
    DocumentItemContainerStyle="{StaticResource DocumentWindowStyle}"
    DocumentItemsSource="{Binding GetDocumentWindows}"
    WindowsClosing="{dxmvvmb:DXEvent Handler='OnWindowsClosing (@args)'}">

...
</docking:DockSite>

 (I'm using the DevExpress MVVM Framework as you can see in the line WindowsClosing).

In the method OnWindowsClosing, which will be accomplished when a docking window is closed, I want to determine the underlying viewmodel of the closed window. For instance, I have three viewmodels: "vm1", "vm2" and "vm3". Adding them to  _documentWindows, I see three DocumentWindows: "Window A" based on "vm1, "Window B" based on "vm2" and "Window C" based on "vm3".

Imagine, the user closes "Window C" (which mustn't be the active window) via the X - Icon. How can I access the underlying viewmodel "vm3"? I can't see a connection between DocumentWindow and the viewmodel.

Thanks in advance

Michael