Sharing state between ViewModels

Question

I have two ViewModels that present the same Model to different Views. One presents the model as an item in a ListBox, the other presents it as a tab in a

Answer 1

TabControl is ItemsControl, so you shouldn't be shy to bind its ItemsSource to ListBox.SelectedITems.

Obviously ViewModel for List should have a property that would produce ViewModel for Tabs:

public TabViewModel ItemTabModel { get { ... } }

And because TabControl is a bit funny, you'd need to add ItemContainerStyle to populate Content for TabControlItem, because the normal ItemTemplate for TableControl only affects headers for tabs.