private MyTextsWrapperEnum?ValidateInput() { MyTextsWrapperEnum?errorMessage = null; if (MyMwcUtils.IsValidUsernameFormat(m_usernameTextbox.Text) == false) { errorMessage = MyTextsWrapperEnum.ValidationUsername; } else if (MyMwcUtils.IsValidPasswordFormat(m_passwordTextbox.Text) == false) { errorMessage = MyTextsWrapperEnum.ValidationPasswordWrong; } else if (MyMwcUtils.IsValidEmailAddress(m_emailTextbox.Text) == false) { errorMessage = MyTextsWrapperEnum.ValidationEmailWrong; } else if (m_passwordTextbox.Text != m_retypePasswordTextbox.Text) { errorMessage = MyTextsWrapperEnum.ValidationPasswordsDoNotMatch; } return(errorMessage); }