LINQ到实体查询与继承？

Question

我有以下型号，请参见图片。

the model

我在弄清楚如何从汽车上获得所有类型的SUV并进行价值求和时遇到问题。

我尝试过

HelpWithSUVSUM = g.OfType<CarsSUV>()
   .Where(d => d.HasPremium == true && (d.Status == "Sold").Sum(d => d.CarValue)

但是它引发了一个错误。任何帮助将不胜感激！

var statsModel =  (
            from c in db.Cars
                join s in db.Salesman on c.SalesmanId equals c.ID into sales
            select new { s, sales }
            into data
            group data by new { data.c.ModelName, data.c.Year } into g
            select new MyData
            {
                CarYear = g.Key.Year,
                SomeCount = g.Count(d => (d.c.Status == "Sold"),
                // etc.. a few more counts
                // NOW I need to get all Cars that are SUV and HasPremium and do a Sum the SUV value
                HelpWithSUVSum = ....
            }
        ).ToList();