正则表达式检测登记用户名是否规范

Regex rex = new Regex(@"[\u4E00-\u9FFF]");var result = rex.Match(registReq.UserName);if (result.Success){    mResp.ErrorInfo = "用户名不能是汉字!";    return true;}Regex rex2 = new Regex(@"^\w$");result = rex2.Match(registReq.UserName);if (!result.Success){    mResp.ErrorInfo = "用户名包含非法字符!";    return true;}