将来自 REST API 的 JSON 响应转换为 DataTable

Question

我正在尝试将来自 REST API 的 json 响应转换为 DataTable。以下是我的代码。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using RestSharp;
using Newtonsoft.Json;
using System.Data;

namespace RestDemo1
{
    class Program
    {
        static void Main(string[] args)
        {
            getEmployeeData();
        }

        public static void getEmployeeData()
        {
            var client = new RestClient("https://crmscf.vidyasystems.com/api/gen/items.php");
            var request = new RestRequest("items");
            var response = client.Execute(request);
            string vJ = "";

            if (response.StatusCode == System.Net.HttpStatusCode.OK)
            {
                string rawResponse = response.Content;
                DataTable tester = (DataTable)JsonConvert.DeserializeObject(rawResponse, (typeof(DataTable)));
            }
        }

        public class Rootobject
        {
            public int success { get; set; }
            public Item[] items { get; set; }

            public class Item
            {
                public string ItemID { get; set; }
                public string ItemName { get; set; }
                public string ItemDesc { get; set; }
                public string MRP { get; set; }
                public string Rate { get; set; }
                public string Unit { get; set; }
                public string Weight { get; set; }
                public string ItemGroup { get; set; }
            }
        }
    }
}

当我尝试将数据转换为表格格式时，出现错误：

DataTable tester = (DataTable)JsonConvert.DeserializeObject(rawResponse, (typeof(DataTable)));

错误消息 - Newtonsoft.Json.JsonSerializationException: '读取 DataTable 时出现意外的 JSON 令牌。预期 StartArray，得到 StartObject。路径''，第 1 行，位置 1。

Answer 1

您的回复是 Rootobject 类型，而不是 DataTable 类型。因此，您不能将 response.Content 反序列化为 DataTable 类型。

你需要做什么：

1. 将response.Content 反序列化为Rootobject 实例。

2. 从Rootobject 实例中提取items（List<Rootobject.Item> 类型的列表）。

3. 通过扩展方法IListExtensions.ToDataTable<T>(this IList<T> list)将List<Rootobject.Item>转换为DataTable。

   string rawResponse = response.Content;
                   
   var root = JsonConvert.DeserializeObject<Rootobject>(rawResponse);
                   
   DataTable dt = root.items.ToDataTable<Rootobject.Item>();
   

   using System.Collections.Generic;
   using System.ComponentModel;
   using System.Data;
   
   public static class IListExtensions
   {
       public static DataTable ToDataTable<T>(this IList<T> list)
       {
           PropertyDescriptorCollection properties = TypeDescriptor.GetProperties(typeof(T));
           DataTable dataTable = new DataTable();
   
           foreach (PropertyDescriptor property in properties)
               dataTable.Columns.Add(property.Name, Nullable.GetUnderlyingType(property.PropertyType) ?? property.PropertyType);
   
           if (list == null)
               return dataTable;
   
           foreach (T item in list)
           {
               DataRow row = dataTable.NewRow();
               foreach (PropertyDescriptor property in properties)
                   row[property.Name] = property.GetValue(item) ?? DBNull.Value;
   
               dataTable.Rows.Add(row);
           }
   
           return dataTable;
       }
   }
   

Answer 2

很抱歉之前的答案，我认为这将解决您的问题：

public static async Task Main(string[] args)
{
    using(HttpClient client = new())
    {
        var response = await client.GetStringAsync("https://crmscf.vidyasystems.com/api/gen/items.php");
        JObject jsonObject = JObject.Parse(response);
        var items = JsonConvert.SerializeObject(jsonObject["items"]);
        DataTable tester = (DataTable)JsonConvert.DeserializeObject(items, (typeof(DataTable)));
    }
    Console.WriteLine("Hello, World!");
}