public override void ViewDidLoad()
        {
            base.ViewDidLoad();
            // Perform any additional setup after loading the view, typically from a nib.

            //dismiss the keyboard on background touch
            View.AddGestureRecognizer(new UITapGestureRecognizer(() =>
            {
                PrincipalTxtField.ResignFirstResponder();
                EntryTxtField.ResignFirstResponder();
                TargetTxtField.ResignFirstResponder();
                StopLTxtField.ResignFirstResponder();
            }));
        }
        void ReleaseDesignerOutlets()
        {
            if (CalculateButton != null)
            {
                CalculateButton.Dispose();
                CalculateButton = null;
            }

            if (EntryTxtField != null)
            {
                EntryTxtField.Dispose();
                EntryTxtField = null;
            }

            if (PrincipalTxtField != null)
            {
                PrincipalTxtField.Dispose();
                PrincipalTxtField = null;
            }

            if (ResultLabel != null)
            {
                ResultLabel.Dispose();
                ResultLabel = null;
            }

            if (StopLTxtField != null)
            {
                StopLTxtField.Dispose();
                StopLTxtField = null;
            }

            if (TargetTxtField != null)
            {
                TargetTxtField.Dispose();
                TargetTxtField = null;
            }
        }