A System.Text.RegularExpressions.RegexRunner object executes a compiled regular expression. A regular expression that is compiled to an assembly becomes a type in that assembly, and an object of that type is typically created using reflection. However, creating an object by reflection is an expensive operation. The System.Text.RegularExpressions.RegexRunnerFactory class improves the performance of the .NET Framework by providing the RegexRunnerFactory.CreateInstance method, which creates a System.Text.RegularExpressions.RegexRunner object for a specific compiled regular expression.