How can I validate a password to contain at least one upper-case or lower-case letter?

Question

Criteria

1. Password length >=8 and <=15
2. One digit(0-9), One alphabet(AZ or az), One special character (@#$*!)

I tried this

((?=.*\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%]).{8,15})

but this checks for both one lower case and upper case , but I need either one.

Answer 1

As the saying goes: "I had a problem, so I thought of using a regex. Now I have two problems".

There's nothing wrong with a good ol' method.

public bool IsPasswordValid(string password)
{
    return password.Length >= 8 &&
           password.Length <= 15 &&
           password.Any(char.IsDigit) &&
           password.Any(char.IsLetter) &&
           (password.Any(char.IsSymbol) || password.Any(char.IsPunctuation)) ;
}

Answer 2

根据此 ，这是一个RegEx，其中包括所有允许的特殊符号：

((?=.*\d)(?=.*[a-zA-Z])(?=.*[@!-'()\+--\/:\?\[-`{}~]).{8,15})

Answer 3

只需删除AZ匹配组并使用RegexOptions.IgnoreCase声明正则表达式即可忽略大小写（即，所提供的字母是大写，小写还是两者都不重要； az组仍将匹配它们）：

new Regex(@"((?=.*\d)(?=.*[a-z])(?=.*[@#$%]).{8,15})", RegexOptions.IgnoreCase)