>>Getting rid of the Regex ? You throw away all the fun ...
>
>:)
>

Frank,

Let me introduce you some fun

(1) I would use ^ and $ - otherwise the pattern may match other things than the intented

(2) The Regex class has some static methods (Match(), Matches(), IsMatch(), Replace() ) you can use without having to instantiate an object
It caches 15 recently used patterns - see CacheSize http://msdn.microsoft.com/en-us/library/system.text.regularexpressions.regex.cachesize.aspx

(3) You can use Groups[ ].Value

			string filepath = @"\folder\aaa.bb";

			string pat = @"^.*\\(?:.+)\\(.+)\.(.+)$";

			var m = Regex.Match(filepath, pat);
			

			if (m.Success)
			{
				Console.WriteLine("{0}", m.Groups[1].Value); // aaa
				Console.WriteLine("{0}", m.Groups[2].Value); // bb
			}
			else
				Console.WriteLine("No match");


			Console.ReadLine();

(4) The Groups[] collection can be indexed by
(a) a non-negative integer. I do not like this. You introduce another pair of parentheses somewhere and you've had it. The indexes have changed
(b) name. This is where named groups come in

			string filepath = @"\folder\aaa.bb";

			string pat = @"^.*\\(?:.+)\\(?<FileStem>.+)\.(?<FileExtension>.+)$";

			var m = Regex.Match(filepath, pat);
			

			if (m.Success)
			{
				Console.WriteLine("{0}", m.Groups["FileStem"].Value); // aaa
				Console.WriteLine("{0}", m.Groups["FileExtension"].Value); // bb
			}
			else
				Console.WriteLine("No match");


			Console.ReadLine();

(5) You can even nest named groups

			string filepath = @"\folder\aaa.bb";

			string pat = @"^.*\\(?:.+)\\(?<FileName>(?<FileStem>.+)\.(?<FileExtension>.+))$";

			var m = Regex.Match(filepath, pat);
			

			if (m.Success)
			{
				Console.WriteLine("{0}", m.Groups["FileStem"].Value); // aaa
				Console.WriteLine("{0}", m.Groups["FileExtension"].Value); // bb
				Console.WriteLine("{0}", m.Groups["FileName"].Value); // aaa.bb
			}
			else
				Console.WriteLine("No match");


			Console.ReadLine();

(6) Let me also introduce zero-width assertions. They can be positive/negative and lookahead/lookbehind
An example: Validate a password, constraints are
(a) at least one lower case char
(b) at least one upper case char
(c) at least one digit
(d) at least 6 chars long

			string[] test = 
			{	"1",	//false
				"2a",	// false
				"H1a4t", // false
				"helloThere",	// false
				"hello1there",	// false
				"hello1There"	// true
			};

			// (?=.*\d.*)   zero-width positve lookeahead.  assure at least one digit
			// (?=.*[a-z].*)   zero-width positve lookeahead.  assure at least one lower case char
			// (?=.*[A-Z].*)   zero-width positve lookeahead.  assure at least one upper case char
			// .{6,}			need at least six chars
			string pat = @"^((?=.*\d.*)(?=.*[a-z].*)(?=.*[A-Z].*).{6,})$";

			foreach( var s in test )
			{
				var m = Regex.Match(s, pat);
				Console.WriteLine("{0}: {1}", m.Success, s);
			}


			Console.ReadLine();

(7) Finally, if you want to discover more fun and goodies - there are plenty

http://msdn.microsoft.com/en-us/library/az24scfc.aspx