#region  DataTable 转换为Json字符串实例方法/// 
/// GetClassTypeJosn 的摘要说明/// 
public class GetClassTypeJosn : IHttpHandler{    /// 
    /// 文件名:DataTable 和Json 字符串互转/// 
     //用法说明实例     public void ProcessRequest(HttpContext context)    {        context.Response.ContentType = "application/json";        context.Response.Charset = "utf-8";        HttpRequest req = context.Request;        string method = req["method"].ToStr().ToLower();       //获取合同明细列表  DataTable 转换为Json字符串        if (method == "txtdate")        {            string json = "";            BO.MakeContractMx bll = new MakeContractMx();            DataSet ds = bll.GetDataTable();            if (ds.Tables.Count > 0)            {                json =ToJson(ds.Tables[0]);            }            context.Response.Write(json);            return;        }    }   public bool IsReusable    {        get        {            return false;        }    }}   #endregion    #region Json字符串转换为DataTable 实例方法    public DataTable JsonToDataTable(json)    {       DataTable  dt= ToDataTable(json);         return dt;    }        #endregion    #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].ToStr());            }            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    #region 转换为string字符串类型    /// 
          
 /// 转换为string字符串类型 /// 
    /// 
          获取需要转换的值    /// 
          需要格式化的位数    /// 
          
           返回一个新的字符串
              public static string ToStr(this object s, string format = "")    {        string result = "";        try        {            if (format == "")            {                result = s.ToString();            }            else            {                result = string.Format("{0:" + format + "}", s);            }        }        catch        {        }        return result;    }   #endregion