>Hi John, I figured it out, ITariffDataImport is the interface my class implements and the string is one of three class properties that I possibly want to group by. I had to use parentheses instead of angle brackets after Func because of UT rendering limitations
>
>

>
>Func(ITariffDataImport, string) grp = null;
>                
>                if (App.ImportSettings.RemoveDuplicates)
>                {
>                    Console.WriteLine("Removing duplicate tariffs...");
>                    
>                    if (App.tariffType == TariffType.BTInternational)
>                        grp = s => s.Destination;
>                    else
>                        if (App.tariffType == TariffType.BTNational118)
>                            grp = s => s.ChargeBand;
>                        else
>                            if (App.tariffType == TariffType.BTNationalIP)
>                                grp = s => s.Service;
>
>                    xlistint.Data = xlistint.Data.GroupBy(grp).Select(s => s.First()).ToList();
>

>
>nice and clean I think.

Neat - but a switch on TarriffType looks cleaner (and more extensible)?:

        switch (App.tarriffType)
        {
            case TarriffType.BTInternational:
                grp = s => s.Destination;
                break;
            case TarriffType.BTNational118:
                 grp = s => s.ChargeBand;
                break;
            case TarriffType.BTNationalIP:
                grp = s => s.Service;
                break;
        }

BTW I think that although UT shows an error with the angle brackets on preview it actually works when you send .....