using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        var input = "portname (some_code_here!=)";

        var pattern = @"\((?<unlocode>[\w\W]+)\)";      

        var regex = new Regex(pattern);

        var match = regex.Match(input);

        if(match.Success)

            Console.WriteLine(match.Groups["unlocode"].Value);  

        else

            Console.WriteLine("No match found");

    }

}