Membership Generate Password alphanumeric only password?

Question

How can I use Membership.GeneratePassword to return a password that ONLY contains alpha or numeric characters? The default method will only guarantee a minimum and not a max

Answer 1

Going from @SollyM's answer, putting a while loop around it, to prevent the very unlikely event of all characters, or too many characters being special characters, and then substring throwing an exception.

private string GetAlphaNumericRandomString(int length)
{
    string randomString = "";
    while (randomString.Length < length)
    {
      //generates a random string, of twice the length specified, to counter the 
      //probability of the while loop having to run a second time
      randomString += Membership.GeneratePassword(length * 2, 0);

      //replace non alphanumeric characters
      randomString = Regex.Replace(randomString, @"[^a-zA-Z0-9]", m => "");
    }
    return randomString.Substring(0, length);
}