Linq used in video is -

IEnum = (From p In dtSheet1.AsEnumerable() Group p By obj_p= New With {Key.P_Employee=p.Item("Employee"),Key.P_Department=p.Item("Department")}  Into MG= Group Select new with { .Employee=obj_p.P_Employee,.Department=obj_p.P_Department,.WorkingHours=MG.Sum(Function( r ) Double.Parse(r.Item("WorkingHours").ToString()))}).ToList

strResult = String.Join(",",IEnum(0).ToString.Split(","c).Select(Function(item) item.ToString.Split("="c)(0).Replace("{","").Trim))+System.Environment.NewLine+ String.Join(System.Environment.NewLine,IEnum.Select(Function(row) String.Join(",",row.ToString.Split(","c).Select(Function(item) item.ToString.Split("="c)(1).Replace("}","").Trim.ToString))))