Question

这是我正在尝试的代码：

string MatchNumberPattern = "^[a-zA-Z0-9]*$";

if (!Regex.IsMatch(cueTextBox9.Text, MatchNumberPattern))
{
    MessageBox.Show("Enter 8 Space Alphanumeric BT ID only");
    cueTextBox9.Text = String.Empty;
}
else
{
    do something();
}

它正在接受aaaaaaaa，但我希望结合使用alpha和数字aaaa1234。

Answer 1

要求输入中显示字母和数字，您需要正向前瞻：

@"^(?=.*[a-zA-Z])(?=.*[0-9])[a-zA-Z0-9]*$"
    ^^^^^^^^^^^^^^^^^^^^^^^^

请参阅regex demo

(?=.*[a-zA-Z])确保有一个字母，(?=.*[0-9])确保输入字符串中有一个数字。

由于您从单行文本框中获取输入，因此在前瞻中使用.是安全的。作为替代方案，您可以使用@"^(?=[^a-zA-Z]*[a-zA-Z])(?=[^0-9]*[0-9])[a-zA-Z0-9]*$"（基于对比原理）。

Answer 2

您可以使用lookahead检查数字并在其他数据之前匹配alpha。

^(?i)(?=\D*\d)\d*[A-Z][A-Z\d]*$

^字符串开头
(?i) flag用于无壳匹配
(?=\D*\d)提前\D*任意数量的非数字，然后是\d数字
如果成功匹配\d*[A-Z]任意数量的数字后跟alpha
[A-Z\d]*匹配任意数量的字母数字字符，直到
$字符串结尾

See demo at regex101

Answer 3

  async Task<string> CheckPasswordAgainstPasswordSettings(string password)
        {
            Regex rxUpper= new Regex(@"[A-Z]");
            Regex rxLower = new Regex(@"[a-z]");



            var passwordcomplexityrulesetttings=  (await _PasswordComplexityRuleService.All()).First();
          if(passwordcomplexityrulesetttings==null)
            {
                return "password valid";
            }
          if(passwordcomplexityrulesetttings.MinLength> password.Length)
            {
                return "password is not of minimum length";

            }
            if (passwordcomplexityrulesetttings.MustContainLettersNumbers)
            {
                if(password.Any(a=>!char.IsDigit(a)&&!char.IsLetter(a)) && !passwordcomplexityrulesetttings.MustContainSpecialCharacters)
                
                {
                    return "password must contain letters and numbers";
                }


            }

            if (passwordcomplexityrulesetttings.MustContainSpecialCharacters)
            {

                if (!password.Any(a => !char.IsDigit(a) && !char.IsLetter(a)))

                {
                    return "password must contain special characters";
                }


            }
            if (passwordcomplexityrulesetttings.MustContainUpperLower)
            {

                if (!rxLower.Match(password).Success||!rxUpper.Match(password).Success)

                {
                    return "password must contain upper and lower case";
                }


            }
            
            return "password valid";

        }

仅用于字母数字的正则表达式不起作用

3 个答案: