private void DeleteUserButton_Click(object sender, RoutedEventArgs e) { if (string.IsNullOrWhiteSpace(ClientIdBox.Text)) { MessageBox.Show("Provide all data"); } else { DeleteUserProcedure deleteUser = new DeleteUserProcedure(Connector, ClientIdBox.Text.NullNumber()); try { var dt = deleteUser.ExecuteQuery(); DataRow row = dt.Rows[0]; if (int.Parse(row["AffectedRows"].ToString() ?? string.Empty) > 0) { MessageBox.Show("Successfully deleted user"); } else { MessageBox.Show("Nothing has been changed!"); } } catch (Exception exception) { MessageBox.Show(exception.Message); } } }