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Hello,

My requirement is to have a username which is having one underscore and should not allow any special characters.I am using client side validation so pls help me with the correct regex.
eg:john_12john


Thanks in advance..
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[no name] 24-Sep-12 3:00am    
Hi,

Your question requires a little research, it does not present any problem or issue.

Check out sites like http://txt2re.com/ which help you to generate such regular expressions.

 
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C#
public bool IsAlphaNumericWithUnderscore(string input)
{
    return Regex.IsMatch(input, "^[a-zA-Z0-9_]+$");
}


or

C#
bool result = input.All(c=>Char.IsLetterOrDigit(c) || c=='_');
 
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Hi,
C#
Regex rx = new Regex("^[a-zA-Z0-9_]*$");
<pre lang="cs">if (rx.IsMatch(UserName.Text))
                    {
                        Valid = true;
                    }
                    else
                    {
MessageBox.Show("Special characters cannot be submitted as a part of the Username (except Underscore).\nPlease re enter the User name and click Button.");
                        UserName.Text = "";
                        UserName.Focus();
                        return;
                    }


try this code, it may helpful for you
 
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v4
I use [A-Za-z0-9_] which allows underscore, but blocks all other special characters.
 
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