遇見零壹魔王

 

    class Order
    {
        public int OrderId { get; set; }
        public string GoodsName { get; set; }
        public DateTime? SoldTime { get; set; }
        public int? Quantity { get; set; }
    }
    class SeedData
    {
        public SeedData()
        {
            this.GenerateOrders = new List<Order>();
            string JsonOrders
                //3月11日
                = "[{\"OrderId\":0,\"GoodsName\":\"Tea\",\"Quantity\":3,\"SoldTime\":\"2019/03/11 10:21:32\"},"
                + "{\"OrderId\":1,\"GoodsName\":\"Tea\",\"Quantity\":5,\"SoldTime\":\"2019/03/11 17:13:09\"},"
                + "{\"OrderId\":2,\"GoodsName\":\"Tea\",\"Quantity\":10,\"SoldTime\":\"2019/03/11 22:01:56\"},"
                //3月13日
                + "{\"OrderId\":3,\"GoodsName\":\"Milk\",\"Quantity\":5,\"SoldTime\":\"2019/03/13 09:13:09\"},"
                + "{\"OrderId\":4,\"GoodsName\":\"Milk\",\"Quantity\":15,\"SoldTime\":\"2019/03/13 10:00:22\"},"
                + "{\"OrderId\":5,\"GoodsName\":\"Milk\",\"Quantity\":20,\"SoldTime\":\"2019/03/13 11:00:33\"},"
                //3月16日
                + "{\"OrderId\":6,\"GoodsName\":\"Soda\",\"Quantity\":5,\"SoldTime\":\"2019/03/16 13:11:44\"},"
                + "{\"OrderId\":7,\"GoodsName\":\"Soda\",\"Quantity\":7,\"SoldTime\":\"2019/03/16 14:11:55\"}]";
            GenerateOrders
                = JsonConvert.DeserializeObject<List<Order>>(JsonOrders);
        }
        public List<Order> GenerateOrders { get; set; }
    }

    class Program
    {
        static void Main(string[] args)
        {
            SeedData seedData = new SeedData();
            List<Order> viewModel = new List<Order>();
            viewModel = seedData.GenerateOrders;
            List<Order> OrderList = viewModel.GroupBy(x => new {
                SoldTime = x.SoldTime.GetValueOrDefault().Date,
                GoodsName = x.GoodsName
            }).Select(x => new Order
            {
                GoodsName = x.Key.GoodsName,
                SoldTime = x.Key.SoldTime,
                Quantity = x.Sum(y => y.Quantity)
            }).ToList();

            foreach (var item in OrderList)
            {
                Console.WriteLine(JsonConvert.SerializeObject(item));
            }


            Console.ReadKey();
        }
    }