Следующий код работает для меня :)
private void PhoneApplicationPage_OrientationChanged(object sender, OrientationChangedEventArgs e)
{
if (e.Orientation == PageOrientation.Landscape ||
e.Orientation == PageOrientation.LandscapeLeft ||
e.Orientation == PageOrientation.LandscapeRight)
{
TitlePanel.Visibility = System.Windows.Visibility.Collapsed;
mediaPlayer.Height = Double.NaN;
mediaPlayer.Width = Double.NaN;
mediaPlayer.VerticalAlignment = System.Windows.VerticalAlignment.Stretch;
mediaPlayer.HorizontalAlignment = System.Windows.HorizontalAlignment.Stretch;
SystemTray.IsVisible = false;
}
else
{
TitlePanel.Visibility = System.Windows.Visibility.Visible;
mediaPlayer.Height = 300;
mediaPlayer.Width = Double.NaN;
mediaPlayer.VerticalAlignment = System.Windows.VerticalAlignment.Top;
mediaPlayer.HorizontalAlignment = System.Windows.HorizontalAlignment.Stretch;
SystemTray.IsVisible = true;
}
}