private void buttonRegister_Click(object sender, EventArgs e) { if (_isUsernameValid && _isRealNameValid && _isPasswordValid && _isPhoneNumberValid && _isEmailAddressValid) { try { if (SupplierDataAccess.IsUsernameExisted(_username)) { MessageBox.Show("用户名已存在"); return; } SupplierDataAccess.InsertSupplier(_username, _realName, _password, _phoneNumber, _emailAddress); MessageBox.Show("注册成功!"); } catch (Exception ex) { MessageBox.Show(ex.Message); return; } Close(); } else { MessageBox.Show("请检查字符串是否匹配"); } }