So this is one of my little side projects. I've been working on it after work for the past few days. It's simple, but as far as I know it's the first of its kind. It's a Silverlight .NET regular expression testing tool. The thing that makes it especially useful is it's real-time highlighting. In other words, it'll highlight all matches found as you change the regular expression and/or the target string.
This isn't a new idea really. I was inspired by a program I've used plenty of times called The Regex Coach. The thing about The Regex Coach though is that it was designed around Perl-compatible regular expressions. .NET regular expressions were designed to be Perl 5 compatible, so The Regex Coach is typically good to use, but not always. I've seen special circumstances where it doesn't behave like my .NET regular expressions do. So ideally it's best to use a true .NET regular expression tester for your .NET applications. And that's why I built Regex Hero.