Using the parent's DataContext (WPF - Dynamic Menu Command Binding)
Use the binding below for your button's command:
{Binding DataContext.CommandName, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type MyUserControl}}}This will tell it to find your UserControl and use its DataContext.
If you want a dirty, MVVM-breaking solution, then set the Tag="{Binding}" on the button and handle the Click event. In the event handler, call the command on your ViewModel.
Ok, then what about modifying your data item class so that it has a property referencing to the whole model view?
If your ItemsSource is of type ObservableCollection<DataItem> then modify DataItem type like this:
public class DataItem{ public BusinessObject Value { get; set; } private ModelView modelView; public ModelView ModelView { get { return modelView; } } public DataItem(ModelView modelView) { this.modelView = modelView; }}