ScrollIntoView for a DataGrid when using MVVM

I just ran into a small problem with a databound DataGrid in Silverlight. If the SelectedItem is changed by the ViewModel, the DataGrid does not scroll to the SelectedItem.
I created a behavior to do this for me. So now if the Selection of the DataGrid is changed, the DataGrid scolls to the selecteditem. (It used the ScrollIntoView method of the DataGrid.)

namespace MVVM.Framework
{public class ScrollIntoViewBehavior : Behavior<DataGrid>
    {
        protected override void OnAttached()
        {
            base.OnAttached();
            this.AssociatedObject.SelectionChanged += new SelectionChangedEventHandler(AssociatedObject_SelectionChanged);
        }
        void AssociatedObject_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (sender is DataGrid)
            {
                DataGrid grid = (sender as DataGrid);
                if (grid.SelectedItem != null)
                {
                    grid.Dispatcher.BeginInvoke(delegate
                    {
                        grid.UpdateLayout();
                        grid.ScrollIntoView(grid.SelectedItem, null);
                    });
                }
            }
        }
        protected override void OnDetaching()
        {
            base.OnDetaching();
            this.AssociatedObject.SelectionChanged -=
                new SelectionChangedEventHandler(AssociatedObject_SelectionChanged);
        }
    }
}

To use this in XAML: (make sure you have included xmlns:fw="clr-namespace:MVVM.Framework" in your header).

<sdk:DataGrid AutoGenerateColumns="true" ItemsSource="{Binding ObjectList}" SelectedItem="{Binding SelectedObject, Mode=TwoWay}" Name="dataGridObjects">
    <i:Interaction.Behaviors>
        <fw:ScrollIntoViewBehavior/>
    </i:Interaction.Behaviors>
</sdk:DataGrid>