Question

I’m trying to generate a random string with 8 characters with the following method and it works perfectly, but It’s 1 little problem.

When I’m printing the string to the screen and copying it from IE to Notepad, sometimes a dash (-) gets added in the middle of the string. What causes this and how can I fix it?

It doesn’t happen alot, maybe 1/10 times , but still, it messes up the string.

    public string generateString()
    {
        int length = 8;
        string str = "";

        string chars = "abcdefghijkmnopqrstuvwxyzABCDEFGH­JKLMNOPQRSTUVWXYZ123456789";

        int charsCount = chars.Length;
        Random random = new Random();
        for (int i = 0; i < length; i++)
        {
            str += chars[random.Next(0, charsCount)];
        }

        return str;
    }

Answer 1

The code you’ve shown won’t do add anything odd to the string. Perhaps it’s the way you’re copying and pasting which is causing a problem. If it’s causing a problem occasionally, look at the HTML source (right-click, View Source) and see whether you can see the problem in there.

EDIT: As Henk has found out, your code apparently isn’t all it seems. How did you end up with the strange character in your source code to start with?

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Having said that, there are certainly things I would change about your code:

• I’d make the name follow .NET naming conventions
• I’d take the Random as a parameter, so you can call it multiple times in quick succession without generating the same string multiple times
• I’d create a char array of the right length, populate it, and then create a new string from that instead of using string concatenation
• I’d make the length of string to generate, and possibly even the character set parameters.

Just to give some idea of what it would look like – in this example I haven’t turned the character set into a parameter, but I’ve extracted it from the method:

private const string ValidCharacters =
    "abcdefghijkmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ123456789";

public static string GenerateString(Random random, int length)
{
    // TODO: Argument validation
    char[] chars = new char[length];
    for (int i = 0; i < chars.Length; i++)
    {
        chars[i] = ValidCharacters[random.Next(ValidCharacters.Length)];
    }
    return new string(chars);
}