} // If we're here, then the custom Form validation rule validated properly return true; } // Perform the necessary operations on the operands, and output the value to the lblResult protected function btnCalculate_Click($strFormId, $strControlId, $strParameter) { switch ($this->lstOperation->SelectedValue) { case 'add': $mixResult = $this->txtValue1->Text + $this->txtValue2->Text; break; case 'subtract': $mixResult = $this->txtValue1->Text - $this->txtValue2->Text; break; case 'multiply': $mixResult = $this->txtValue1->Text * $this->txtValue2->Text; break; case 'divide': $mixResult = $this->txtValue1->Text / $this->txtValue2->Text; break; default: throw new Exception('Invalid Action'); } if (isset($mixResult)) { $this->lblResult->Text = '<b>Your Result:</b> ' . $mixResult; } } } // And now run our defined form CalculatorForm::Run('CalculatorForm');