Hello,

how can I trace this regular expression in c#:

@"\s*\d{1,3}\s*"

The string is a verbatim string in c#. So ' will not work to take {} as characters and not as keywords.
The {1,3} is interpreted as a parameter from the list behind the output string: trace(string, parameter list).

The Trace-function always throws a System.FormatException.