List<TestData> list = new List<TestData>();
            list.Add(new TestData() { Name = "A", Count = 3, BatNum = "001" });
            list.Add(new TestData() { Name = "A", Count = 3, BatNum = "001" });
            list.Add(new TestData() { Name = "A", Count = 3, BatNum = "002" });
            list.Add(new TestData() { Name = "b", Count = 3, BatNum = "001" });
            list.Add(new TestData() { Name = "b", Count = 6, BatNum = "002" });
            list.Add(new TestData() { Name = "b", Count = 3, BatNum = "003" });
            list.Add(new TestData() { Name = "b", Count = 5, BatNum = "001" });
            List<TestData> newlist = new List<TestData>();
            var query = list.OrderBy(x => x.Name)
                         .GroupBy(x => new { x.Name, x.BatNum })
                         .Select(x => new TestData() { Name = x.Key.Name, Count = x.Sum(y => y.Count), BatNum = x.Key.BatNum })
                         .Aggregate((x, y) =>
                         {
                             if (newlist.Count == 0)
                                 newlist.Add(x);
                             if (x.Name == y.Name)
                                 newlist.Add(new TestData() { Name = ",,", Count = y.Count, BatNum = y.BatNum });
                             else
                                 newlist.Add(y);
                             return y;
                         });
            foreach (TestData t in newlist)
                Console.WriteLine("Name={0}  Count={1}  BatNum=\"{2}\"", t.Name, t.Count, t.BatNum);
/*
Name=A  Count=6  BatNum="001"
Name=,,  Count=3  BatNum="002"
Name=b  Count=8  BatNum="001"
Name=,,  Count=6  BatNum="002"
Name=,,  Count=3  BatNum="003"
*/