private void OnOperatorClick(object sender, EventArgs e) { Button b = (Button)sender; _operation = b.Text; try { _calculatorEngine.SubmitOperation("=", Convert.ToDecimal(_shownText)); _isOperatorPressed = true; _equation = _shownText + " " + _operation; _calculatorView.EquationLabel(_equation); } catch (FormatException) { _messageBoxDisplayService.Show("Enter a valid value"); _shownText = "0"; _equation = "0"; //vreau ca operatia sa ramana salvata in eventualitatea in care userul a realizat din greseala o operatie "nevalida" si doreste sa continue efectuarea acesteia, cu un operand valid, dupa ce curata ResultBox-ul. } }