I looked around on stackoverflow, etc, but haven't found a good answer for this..Does regex support writing a rule like this? If so is there any regex experts our there who can help me write this, I am a big newb to regex and in a time crunch...
I know I can do this with a manual function in c# using c# char, number methods, but I would like to use regex if I can for this..
Requirement :
You can use this regex
^(?=(.*\d){2})(?=.*[a-z])(?=.*[A-Z])(?=.*[^a-zA-Z\d]).{8,}$
--------- --------------------- --------------- -----
| | | |->match 8 or more characters
| | |->match further only if theres anything except letter or digit
| |->match further only if there is an upper-lower case letter
|
|->match further only if there are two digits anywhere
+1 for hacking that together.
(?= in regular expression. Great work.
You are much better off writing a simple validation routine for a password that has all of these checks.
A regular expression doesn't seem as the best (or most extensible) solution for this particular problem.
if(password.Length < 8)
return false;
var letters = 0;
var digits = 0;
var uppers = 0;
var lowers = 0;
var symbols = 0;
foreach(var ch in password)
{
if (char.IsLetter(ch)) letters++;
if (char.IsDigit(ch)) digits++;
....
}
if(letters < 2) return false;
...
I recommend going the way Oded's answer did, but I think LINQ is a more readable and explicit validation mechanism in this case.
string p = "psW%Rd32";
return p.Length >= 8 &&
p.Count(c => char.IsDigit(c)) >= 2 &&
p.Count(c => char.IsUpper(c)) >= 1 &&
p.Count(c => char.IsLower(c)) >= 1) ...
Count).
+1 - Though it would require many iterations through the string, it's easy to read and well organized.
You may try this method.
private bool ValidatePassword(string password, out string ErrorMessage)
{
var input = password;
ErrorMessage = string.Empty;
if (string.IsNullOrWhiteSpace(input))
{
throw new Exception("Password should not be empty");
}
var hasNumber = new Regex(@"[0-9]+");
var hasUpperChar = new Regex(@"[A-Z]+");
var hasMiniMaxChars = new Regex(@".{8,8}");
var hasLowerChar = new Regex(@"[a-z]+");
var hasSymbols = new Regex(@"[!@#$%^&*()_+=\[{\]};:<>|./?,-]");
if (!hasLowerChar.IsMatch(input))
{
ErrorMessage = "Password should contain At least one lower case letter";
return false;
}
else if (!hasUpperChar.IsMatch(input))
{
ErrorMessage = "Password should contain At least one upper case letter";
return false;
}
else if (!hasMiniMaxChars.IsMatch(input))
{
ErrorMessage = "Password should not be less than or greater than 8 characters";
return false;
}
else if (!hasNumber.IsMatch(input))
{
ErrorMessage = "Password should contain At least one numeric value";
return false;
}
else if (!hasSymbols.IsMatch(input))
{
ErrorMessage = "Password should contain At least one special case characters";
return false;
}
else
{
return true;
}
}
