Detecting that the input string just consist of digits or letters

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Hello,

In my program, there is a textbox asking the user to create a Username for himself. The Username should consist of digits or letters only. I mean, @, &, # or ... should be excluded. How can I detect that the entered Username just includes these legal (digits or letters) entries.

Thanks a lot

Posted 12-Aug-10 8:57am

ahhashemi

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Samuel Cherinet · Accepted Answer · 2010-08-12T09:10:00

Solution 1

one way to do that is using regular expressions ...

Regex regex = new Regex("^[A-Za-z0-9]+$");
            if (regex.IsMatch(textBox1.Text))
                MessageLabel.Text= "valid";
            else
                MessageLabel.Text= "Not Valid";

just off the top of my head ...

Posted 12-Aug-10 9:10am

Samuel Cherinet

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ahhashemi 12-Aug-10 15:25pm

Reason for my vote of 5
Dear samqty

Your answer was exactly what I was looking for and hit the target. Thanks a lot and Good luck.

Jimmanuel · Accepted Answer · 2010-08-12T09:18:00

Solution 2

If you don't want to use Regex you can loop through each character in the string and test it with char.IsLetterOrDigit[^]

Posted 12-Aug-10 9:18am

Jimmanuel