private void buttonSubmit_Click(object sender, EventArgs e) { if (textBoxLoanId.Text != null && textBoxAmount.Text != null) { decimal decimalAmount; if ((new Regex(@"^\d+$").Match(textBoxLoanId.Text).Success) && decimal.TryParse(textBoxAmount.Text, out decimalAmount)) { databaseService.AddLoanTransaction(new LoanPaymentVO(-1, Convert.ToInt32(textBoxLoanId.Text), Convert.ToDouble(textBoxAmount.Text))); WindowManager.navigateToForm(this, this.GetType(), typeof(Homescreen)); } } else { MessageBox.Show("Invalid Loan Id or Amount. Please try again."); } }