using System;

using System.Collections.Generic;

using System.Web;

using System.Web.Script.Serialization;

using System.Data;

namespace Utils

{

    /// <summary>

    /// JSON帮助类

    /// </summary>

    public class JsonHelper

    {

        /// <summary>

        /// 对象转JSON

        /// </summary>

        /// <param name="obj">对象</param>

        /// <returns>JSON格式的字符串</returns>

        public static string ObjectToJSON(object obj)

        {

            JavaScriptSerializer jss = new JavaScriptSerializer();

            try

            {

                return jss.Serialize(obj);

            }

            catch (Exception ex)

            {

                throw new Exception("JSONHelper.ObjectToJSON(): " + ex.Message);

            }

        }

        /// <summary>

        /// 数据表转键值对集合

        /// 把DataTable转成 List集合, 存每一行

        /// 集合中放的是键值对字典,存每一列

        /// </summary>

        /// <param name="dt">数据表</param>

        /// <returns>哈希表数组</returns>

        public static List<Dictionary<string, object>> DataTableToList(DataTable dt)

        {

            List<Dictionary<string, object>> list

                 = new List<Dictionary<string, object>>();

            foreach (DataRow dr in dt.Rows)

            {

                Dictionary<string, object> dic = new Dictionary<string, object>();

                foreach (DataColumn dc in dt.Columns)

                {

                    dic.Add(dc.ColumnName, dr[dc.ColumnName]);

                }

                list.Add(dic);

            }

            return list;

        }

        /// <summary>

        /// 数据集转键值对数组字典

        /// </summary>

        /// <param name="dataSet">数据集</param>

        /// <returns>键值对数组字典</returns>

        public static Dictionary<string, List<Dictionary<string, object>>> DataSetToDic(DataSet ds)

        {

            Dictionary<string, List<Dictionary<string, object>>> result = new Dictionary<string, List<Dictionary<string, object>>>();

            foreach (DataTable dt in ds.Tables)

                result.Add(dt.TableName, DataTableToList(dt));

            return result;

        }

        /// <summary>

        /// 数据表转JSON

        /// </summary>

        /// <param name="dataTable">数据表</param>

        /// <returns>JSON字符串</returns>

        public static string DataTableToJSON(DataTable dt)

        {

            return ObjectToJSON(DataTableToList(dt));

        }

        /// <summary>

        /// JSON文本转对象,泛型方法

        /// </summary>

        /// <typeparam name="T">类型</typeparam>

        /// <param name="jsonText">JSON文本</param>

        /// <returns>指定类型的对象</returns>

        public static T JSONToObject<T>(string jsonText)

        {

            JavaScriptSerializer jss = new JavaScriptSerializer();

            try

            {

                return jss.Deserialize<T>(jsonText);

            }

            catch (Exception ex)

            {

                throw new Exception("JSONHelper.JSONToObject(): " + ex.Message);

            }

        }

        /// <summary>

        /// 将JSON文本转换为数据表数据

        /// </summary>

        /// <param name="jsonText">JSON文本</param>

        /// <returns>数据表字典</returns>

        public static Dictionary<string, List<Dictionary<string, object>>> TablesDataFromJSON(string jsonText)

        {

            return JSONToObject<Dictionary<string, List<Dictionary<string, object>>>>(jsonText);

        }

        /// <summary>

        /// 将JSON文本转换成数据行

        /// </summary>

        /// <param name="jsonText">JSON文本</param>

        /// <returns>数据行的字典</returns>

        public static Dictionary<string, object> DataRowFromJSON(string jsonText)

        {

            return JSONToObject<Dictionary<string, object>>(jsonText);

        }

    }

}