title: How to find out if string contains non-alpha numeric characters in C#/.NET 2.0?
body: <p>Allowed characters are (at least) A-Z, a-z, 0-9, ö, Ö, ä, ä, å, Å and german, latvian, estonian (if any) special chars? Is there ready-made method or do i have to make blacklist (non-allowed chars) and regular expressions IsMatch? If no ready-made how to use blacklist?</p>