使用c#写一个点餐系统

好的，点餐系统可以分为客户端和服务端两部分。客户端负责展示菜单、接收用户的点餐信息以及向服务端发送请求。服务端负责处理请求，保存订单信息并提供管理订单的功能。以下是一个简单的C#点餐系统示例：

### 客户端

using System;
using System.Net.Http;
using System.Text.Json;
using System.Collections.Generic;

namespace OrderClient
{
    class Program
    {
        static HttpClient client = new HttpClient();
        static JsonSerializerOptions options = new JsonSerializerOptions
        {
            PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
            WriteIndented = true
        };

        static void Main(string[] args)
        {
            while (true)
            {
                Console.WriteLine("欢迎使用点餐系统！");
                Console.WriteLine("请选择您要点的菜品：");

                // 获取菜单信息
                var menu = GetMenu();
                foreach (var item in menu)
                {
                    Console.WriteLine($"{item.Id}: {item.Name} - {item.Price}元");
                }

                // 输入订单信息
                Console.Write("请输入您要点的菜品编号，多个菜品请用逗号隔开：");
                var input = Console.ReadLine();

                // 发送订单信息到服务端
                var order = new Order { Items = input.Split(',') };
                var response = client.PostAsJsonAsync("http://localhost:5000/orders", order).Result;
                if (response.IsSuccessStatusCode)
                {
                    Console.WriteLine("订单提交成功！");
                }
                else
                {
                    Console.WriteLine("订单提交失败，请稍后再试！");
                }

                Console.WriteLine("按任意键继续点餐，按q退出程序。");
                var key = Console.ReadKey();
                if (key.KeyChar == 'q')
                {
                    break;
                }
            }
        }

        static List<MenuItem> GetMenu()
        {
            var response = client.GetAsync("http://localhost:5000/menu").Result;
            if (response.IsSuccessStatusCode)
            {
                var content = response.Content.ReadAsStringAsync().Result;
                return JsonSerializer.Deserialize<List<MenuItem>>(content, options);
            }
            else
            {
                return new List<MenuItem>();
            }
        }
    }

    class Order
    {
        public string[] Items { get; set; }
    }

    class MenuItem
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public decimal Price { get; set; }
    }
}

### 服务端

using System;
using System.Collections.Generic;
using System.Linq;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;

namespace OrderServer.Controllers
{
    [ApiController]
    [Route("[controller]")]
    public class OrdersController : ControllerBase
    {
        private static readonly List<Order> orders = new List<Order>();
        private static readonly List<MenuItem> menu = new List<MenuItem>
        {
            new MenuItem { Id = 1, Name = "麻婆豆腐", Price = 18.5M },
            new MenuItem { Id = 2, Name = "宫保鸡丁", Price = 22M },
            new MenuItem { Id = 3, Name = "清蒸鲈鱼", Price = 56M },
            new MenuItem { Id = 4, Name = "红烧肉", Price = 38M },
            new MenuItem { Id = 5, Name = "酸菜鱼", Price = 48M }
        };

        private readonly ILogger<OrdersController> _logger;

        public OrdersController(ILogger<OrdersController> logger)
        {
            _logger = logger;
        }

        [HttpGet]
        [Route("menu")]
        public List<MenuItem> GetMenu()
        {
            return menu;
        }

        [HttpPost]
        public IActionResult Post([FromBody] OrderRequest request)
        {
            var order = new Order
            {
                Id = Guid.NewGuid().ToString(),
                Items = request.Items.Select(GetMenuItemById).ToList(),
                TotalPrice = request.Items.Select(GetMenuItemById).Sum(item => item.Price)
            };
            orders.Add(order);
            return Ok();
        }

        [HttpGet]
        public List<Order> Get()
        {
            return orders;
        }

        [HttpDelete]
        public IActionResult Delete(string id)
        {
            var order = orders.FirstOrDefault(o => o.Id == id);
            if (order != null)
            {
                orders.Remove(order);
                return Ok();
            }
            else
            {
                return NotFound();
            }
        }

        private MenuItem GetMenuItemById(string id)
        {
            if (int.TryParse(id, out var itemId))
            {
                return menu.FirstOrDefault(item => item.Id == itemId);
            }
            else
            {
                throw new ArgumentException("Invalid item id", nameof(id));
            }
        }
    }

    public class OrderRequest
    {
        public string[] Items { get; set; }
    }

    public class Order
    {
        public string Id { get; set; }
        public List<MenuItem> Items { get; set; }
        public decimal TotalPrice { get; set; }
    }

    public class MenuItem
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public decimal Price { get; set; }
    }
}

以上代码仅供参考，实际生产环境中需要考虑更多的安全性、性能等方面。