How to validate Password text box control to to allow only letters & special characters

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how to validate password to allow only letters and special character , for this i used Regular expresion validation but it was not properly working like i used ^[a-zA-Z!@#$%^&*]+$ but this code what fail when i entere only letter it was not throwing any type of err ..

Posted 21-Apr-13 2:57am

Alok.singh1166

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OriginalGriff 21-Apr-13 9:39am

I think we need more information, really.
Perhaps an example of the inputs you gave, and what happened, together with what you expected to happen.
The relevant code fragment would probably help too.
Use the "Improve question" widget to edit your question and provide better information.

Alok.singh1166 21-Apr-13 12:25pm

Hi OriginalGriff according to my requirement in password txt field user should enter at least one upper case ,one lower case and one special character .at least one is mandatory until & unless it should throw error.pls help

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Pallavi Waikar · Accepted Answer · 2013-04-21T04:41:00

Solution 1

As i understand you want at least one letter and at least one special character ..then try this regex..hope this will help

C#

if (System.Text.RegularExpressions.Regex.IsMatch("$#%hg#$Y%#$", @"^(?=.*[a-zA-Z])(?=.*[!@#$%^&*])"))
                MessageBox.Show("Match found");
            else
                MessageBox.Show("Match not found");

Updated answer
for "Enter at least one uppercase and leter in uppercase and lower case & special character"

C#

if (System.Text.RegularExpressions.Regex.IsMatch("$#%hg#$Y%#$", @"^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%^&*])"))
               MessageBox.Show("Match found");
           else
               MessageBox.Show("Match not found");

Posted 21-Apr-13 4:41am

Pallavi Waikar

Updated 21-Apr-13 5:46am

v2

Comments

Alok.singh1166 21-Apr-13 11:35am

THANK'S PALLAVI
this is the code i am using but what i want in password txt field user there should be at least one upper case one lower case and one special character .but this regex expresion is not throwing any error while entering only charaters.pls help

private void txtpassword(object sender, EventArgs e)
{
try
{
if (System.Text.RegularExpressions.Regex.IsMatch("$#%hg#$Y%#$", @"^(?=.*[a-zA-Z])(?=.*[!@#$%^&*])"))
return;

}
catch (Exception ey)
{
label3.Visible = true;
label3.Text = "Enter at least one uppercase and leter in uppercase and lower case & special character";
}
}

Pallavi Waikar 21-Apr-13 11:48am

it's easy only u have to separate (?=.*[a-zA-Z]) into (?=.*[a-z])(?=.*[A-Z]) ...because then after upper and lower letter will checked independently ..check updated answer

Alok.singh1166 21-Apr-13 12:11pm

Hi pallavi i used this code but its not what i want .according to my need user should enter atleast one upper case,lower case and special character.if user entered only uppercase and not entered any special character it should throw error..

Pallavi Waikar 21-Apr-13 12:32pm

OK..try this code
private void txtpassword(object sender, EventArgs e)
{
try
{
if (System.Text.RegularExpressions.Regex.IsMatch("$#%hg#$Y%#$", @"^(?=.*[a-zA-Z])(?=.*[!@#$%^&*])"))
return;
else
{
label1.Visible = true;
label1.Text = "Enter at least one uppercase and leter in uppercase and lower case & special character";
}

}
catch (Exception ey)
{
label3.Visible = true;
label3.Text = "Enter at least one uppercase and leter in uppercase and lower case & special character";
}

Alok.singh1166 21-Apr-13 12:40pm

I entered only letters no special character i used and it is not throwing any error.

OriginalGriff 22-Apr-13 3:15am

To be honest, a regex is not a good solution for that kind of checking - it can be done but it's horribly complex and very hard to maintain because regexes aren't designed for counting!
A much, much easier solution for this is to use three regexes:
private Regex upperCase = new Regex("[A-Z]", RegexOptions.Compiled);
private Regex lowerCase = new Regex("[a-z]", RegexOptions.Compiled);
private Regex specialCh = new Regex("[!@#$%^&*]", RegexOptions.Compiled);

private void tbPassword_TextChanged(object sender, EventArgs e)
{
string pw = tbPassword.Text;
int lower = lowerCase.Matches(pw).Count;
int upper = upperCase.Matches(pw).Count;
int special = specialCh.Matches(pw).Count;
labPasswordStatus.Text = lower > 0 && upper > 0 && special > 0 ? "OK" : "Bad";
}
It is also a lot, lot easier to maintain should the rules change and you want to force a digit as well.

Pallavi Waikar 22-Apr-13 3:36am

Sir it is working on my side..i think he is beginner that's why not able to implement it.This regex is combination of all tree condition..i am still not able understand why he want throw error although he can able to show error in else part.

Alok.singh1166 23-Apr-13 10:32am

Hi Pallavi your code is working fine but when you will enter only upper case and you will not use any lower case and special character at that time it is not throwing any error.you try entering only upper case and see no error will come .but what i want if user enters only uppercase then it should ask to enter upper case lower case and special character..

Pallavi Waikar 23-Apr-13 10:41am

ok u want compulsory one uppercase letter ,one lowercase letter ,one special character letter in your password..and what u have post in ur above comment ur have not reffed my updated answer that's why ur facing problem ..again try below code :)
if (System.Text.RegularExpressions.Regex.IsMatch("^ggggHHHH^^^^", @"^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%^&*])"))
{

return;

}
else
{
label1.Visible = true;
label1.Text = "Enter at least one uppercase and leter in uppercase and lower case & special character";
}
i have checked it and it is allowing only password with all three condition

Pallavi Waikar 23-Apr-13 10:48am

is it working...if not u can point it out ur welcome