Restrict ViewController to Portrait mode does not work!

gistfile1.txt

        public partial class PortraitOnlyViewController : UIViewController
        {
                public PortraitOnlyViewController () : base ("PortraitOnlyViewController", null)
                {
                }
 
                public override void DidReceiveMemoryWarning ()
                {
                        // Releases the view if it doesn't have a superview.
                        base.DidReceiveMemoryWarning ();
 
                        // Release any cached data, images, etc that aren't in use.
                }
 
                [Obsolete ("Deprecated in iOS6. Replace it with both GetSupportedInterfaceOrientations and PreferredInterfaceOrientationForPresentation")]
                public override bool ShouldAutorotateToInterfaceOrientation (UIInterfaceOrientation toInterfaceOrientation)
                {
                        // we're passed to orientation that it will rotate to. in our case, we could
                        // just return true, but this switch illustrates how you can test for the
                        // different cases
                        switch (toInterfaceOrientation)
                        {
                        case UIInterfaceOrientation.Portrait:
                                return true;
                        }
                        return false;
                }
 
                public override bool ShouldAutorotate ()
                {
                        return false;
                }
 
                public override UIInterfaceOrientationMask GetSupportedInterfaceOrientations ()
                {
                        return UIInterfaceOrientationMask.Portrait;
                }
 
                public override UIInterfaceOrientation PreferredInterfaceOrientationForPresentation ()
                {
                        return UIInterfaceOrientation.Portrait;
                }
 
                public override void ViewDidLoad ()
                {
                        base.ViewDidLoad ();
                }
        }