private void btnSignIn_Click(object sender, RoutedEventArgs e) { try { bool isValidUser = BusinessLogic.IsValidUser(txtUserName.Text, txtPassword.Password); if (isValidUser) { DeleteClients deleteClientForm = new DeleteClients(); deleteClientForm.Show(); this.Close(); } else { Helper.ShowErrorMessageBox("Invalid user name or password!"); } } catch (Exception ex) { Helper.LogException(ex); } }