String.Format in linq request

I'm stuck in someone else's problem. I have a class CashGameGeneralViewModelthat looks like

public class CashGameGeneralViewModel
{
    public string Limit { get; set; }
    public int HandsPlayed { get; set; }

    public float AmountWon { get; set; }
}

Here is a method that should return all the hands a particular player plays:

public List<CashGameGeneralViewModel> GetAllHands(string playerToFind)
    {
        HoldemHandContext db = new HoldemHandContext();
        int playerId = GetPlayerId(playerToFind);
        var holdemHandResult = (from phh in db.PlayersInHoldemHands
                                from hh in db.HoldemHands
                                where hh.Id == phh.HandPlayed && phh.PlayerId == playerId
                                select new CashGameGeneralViewModel()
                                           {
                                               Limit = //"some text",
                                               String.Format("{0:0.00}", hh.SBlindAmount) + "/" +
                                               String.Format("{0:0.00}", hh.BBlindAmount),
                                               HandsPlayed = db.HoldemHands.Distinct().Count(),
                                               AmountWon = 0
                                           }
                                ).ToList();

        return holdemHandResult;
    }

    public int GetPlayerId(string playerToFind)
    {
        HoldemHandContext db = new HoldemHandContext();
        int playerId = (from p in db.Players
                        where p.ScreenName == playerToFind
                        select p.Id).FirstOrDefault();

        return playerId;
    }

Now the problem is

Limit = //"some text",
String.Format("{0:0.00}", hh.SBlindAmount) + "/" +
String.Format("{0:0.00}", hh.BBlindAmount)

part. hh.SBlindAmountand hh.BBlindAmountare float values. I wanted to use String.Formatit because it was 0.10shortened to 0.1, and in the lowercase format I got it as if I wanted to. But I get an exception that says 'The invocation of the constructor on type 'PokerRecord.View.CashGameGeneralUC' that matches the specified binding constraints threw an exception.' Line number '60' and line position '18'.. When I delete string.format and put in some kind of “normal” string, everything works fine ... Does anyone know why?