C# 数据库查询结果table转化为json字符串，或反向把json字符串转换为DataTable数据集合 以下代码经实践简单可用。

转换通用类定义：

using System;using System.Collections.Generic;using System.Collections;using System.Linq;using System.Web;using System.Web.Script.Serialization;using System.Data;using System.Reflection;namespace testcsoft{    public static class jsonObject     {     #region DataTable 转换为Json 字符串    /// 
    /// DataTable 对象 转换为Json 字符串    /// 
    ///     /// 
        public static string ToJson(this DataTable dt)    {        JavaScriptSerializer javaScriptSerializer = new JavaScriptSerializer();        javaScriptSerializer.MaxJsonLength = Int32.MaxValue; //取得最大数值        ArrayList arrayList = new ArrayList();        foreach (DataRow dataRow in dt.Rows)        {            Dictionary
    
      dictionary = new Dictionary
     
      ();  //实例化一个参数集合            foreach (DataColumn dataColumn in dt.Columns)            {                dictionary.Add(dataColumn.ColumnName, dataRow[dataColumn.ColumnName].ToString());            }            arrayList.Add(dictionary); //ArrayList集合中添加键值        }         return javaScriptSerializer.Serialize(arrayList);  //返回一个json字符串    }    #endregion         #region Json 字符串 转换为 DataTable数据集合    /// 
      
    /// Json 字符串 转换为 DataTable数据集合    /// 
    /// 
          /// 
          public static DataTable ToDataTable(this string json)    {        DataTable dataTable = new DataTable();  //实例化        DataTable result;        try        {            JavaScriptSerializer javaScriptSerializer = new JavaScriptSerializer();            javaScriptSerializer.MaxJsonLength = Int32.MaxValue; //取得最大数值            ArrayList arrayList = javaScriptSerializer.Deserialize
      
       (json);            if (arrayList.Count > 0)            {                foreach (Dictionary
       
         dictionary in arrayList)                {                    if (dictionary.Keys.Count
        
         () == 0)                    {                        result = dataTable;                        return result;                    }                    if (dataTable.Columns.Count == 0)                    {                        foreach (string current in dictionary.Keys)                        {                            dataTable.Columns.Add(current, dictionary[current].GetType());                        }                    }                    DataRow dataRow = dataTable.NewRow();                    foreach (string current in dictionary.Keys)                    {                        dataRow[current] = dictionary[current];                    }                     dataTable.Rows.Add(dataRow); //循环添加行到DataTable中                }            }        }        catch        {        }        result = dataTable;        return result;    }    #endregion          }}
        
       
      
     
    

使用方法：

DataTable -->  json :

string  json = jsonObject.ToJson(ds.Tables[0]);     

 // 其中  ds.Tables[0]  是数据库查询的表

  json -->  DataTable :

DataTable dt = jsonObject.ToDataTable(json);

这是测试从数据库获取数据并table和json互转结果