[Windows 8] How to check windows 8 UI modes by C#

Sample:

using Windows.UI.ViewManagement;

private void pageRoot_SizeChanged(object sender, SizeChangedEventArgs e)
{
    ApplicationViewState viewState = ApplicationView.Value;
    if (viewState == ApplicationViewState.Filled)
    {
        System.Diagnostics.Debug.WriteLine("viewState is Filled");
    }
    else if (viewState == ApplicationViewState.FullScreenLandscape)
    {
        System.Diagnostics.Debug.WriteLine("viewState is FullScreenLandscape");
    }
    else if (viewState == ApplicationViewState.Snapped)
    {
        System.Diagnostics.Debug.WriteLine("viewState is Snapped");
    }
    else if (viewState == ApplicationViewState.FullScreenPortrait)
    {
        System.Diagnostics.Debug.WriteLine("viewState is FullScreenPortrait");
    }
    else
    {
        System.Diagnostics.Debug.WriteLine("viewState is something unexpected");
    }
}