How do you get data from controls on pages on a Tab Control

Question

I've got a WPF tab control that contain several duplicate controls as Tab Page content

<TabControl ItemsSource="{Binding}" Name="tabControl">
    <TabControl.ItemTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding Name}"/>
        </DataTemplate>
    </TabControl.ItemTemplate>
    <TabControl.ContentTemplate>
        <DataTemplate>
            <local:InnerDataEntryControl DataContext="{Binding Data}"/> 
        </DataTemplate>
    </TabControl.ContentTemplate>
</TabControl>

On the InnerDataEntry control there is a list box. I've got a command on the outer form that requires the selected items from the list box on the control. I can't figure out how to access the list box on the tab control itself. When I try to query the selected items, I get the bound items and not the list box itself.

I don't want to pollute the business layer with an 'IsSelected' property on my list items, and I suppose I could create a view model if necessary, but it just seems wrong that I can't get information about the actual content control of a tab page.

I hope that I'm just missing something obvious.

Answer 1

This was asked earlier in my WPF experience. To close the loop on the question, I'm going to post a link to the MSDN Magazine entry on the subject of MVVM.

Ultimately, the solution involves the creation of a view model that has the necessary properties bound to the parts of the tab control such that the view model doesn't need access in the way that I'm describing. Instead, the view model acts directly on the data that that is bound without having to reference the view directly.