Datatable/Dataset 转 JSON方法

当数据库表的数据在一般处理程序中查出来需要将这个表数据返回到前台的jquery中，需要将数据拼成json字符串形式，
这里是将数据库数据查出放在Datatable中，然后在一般处理程序中将datatable转成json的几个方法，根据不同的情况调用不同的方法（Dataset集合中的数据也可以遍历每一个索引上的datatable调用此方法）。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using System.Text;

/// <summary>
///DataHelper 的摘要说明
/// </summary>
public class DataHelper
{
    public DataHelper()
    {
        //
        //TODO: 在此处添加构造函数逻辑
        //
    }
    #region DataTable转Json
    /// <summary>
    /// DataTable转Json for DataGrid
    /// </summary>
    /// <param name="_dt"></param>
    /// <returns></returns>
    public static string ToDataGrid(DataTable _dt)
    {
        string GridJson = string.Empty;
        try
        {
            GridJson = "{\"total\":" + _dt.Rows.Count + ",\"rows\":[";
            for (int i = ; i < _dt.Rows.Count; i++)
            {
                GridJson += "{";
                string strTemp = "";
                for (int j = ; j < _dt.Columns.Count; j++)
                {
                    strTemp = (j == _dt.Columns.Count -  ? "" : ",");
                    GridJson += "\"" + _dt.Columns[j].ColumnName.ToString() + "\":\"" + _dt.Rows[i][j].ToString().Trim() + "\"" + strTemp;
                }
                strTemp = (i == _dt.Rows.Count -  ? "}" : "},");
                GridJson += strTemp;
            }
            GridJson += "]}";
            //  Rev_DBPublic.Rev_WriteLog.WriteLog("PubErrorLogPath", "ToDataGrid" + "123", GridJson);
        }
        catch (Exception ee)
        {
            Rev_DBPublic.Rev_WriteLog.WriteLog("PubErrorLogPath", "ToDataGrid" + "", GridJson + "Err:" + ee.Message);
        }
        return GridJson;
    }
    #endregion
    /// <summary>
    /// 将Datatable 中得数据行进行分页,并将页内数据返回
    /// </summary>
    /// <param name="dt"></param>
    /// <param name="pageSize">行数</param>
    /// <param name="pageIndex">第几页</param>
    /// <returns></returns>
    public static DataTable DataTableToPager(DataTable dt, int pageSize, int pageIndex)
    {
        if (dt == null || dt.Rows.Count == )
        {
            return dt;
        }
        DataTable returnValue = null;

        DataColumn dc = new DataColumn("rowindex", Type.GetType("System.Int32"));
        dt.Columns.Add(dc);

        for (int i = ; i < dt.Rows.Count; i++)
        {
            dt.Rows[i]["rowindex"] = i;
        }

        int _start = (pageIndex - ) * pageSize;
        int _end = _start + pageSize;

        DataView dv = dt.DefaultView;
        dv.RowFilter = string.Format("rowindex>={0} and rowindex<{1}", _start, _end);
        returnValue = dv.ToTable();
        return returnValue;

    }
    #region DataTable转Json
    /// <summary>
    /// DataTable转Json for DataGrid
    /// </summary>
    /// <param name="_dt"></param>
    /// <returns></returns>
    public static string ToDataGridPage(DataTable _dt, int _row)
    {
        string GridJson = "{\"total\":" + _row + ",\"rows\":[";
        for (int i = ; i < _dt.Rows.Count; i++)
        {
            GridJson += "{";
            string strTemp = "";
            for (int j = ; j < _dt.Columns.Count; j++)
            {
                strTemp = (j == _dt.Columns.Count -  ? "" : ",");
                GridJson += "\"" + _dt.Columns[j].ColumnName.ToString() + "\":\"" + _dt.Rows[i][j].ToString() + "\"" + strTemp;
            }
            strTemp = (i == _dt.Rows.Count -  ? "}" : "},");
            GridJson += strTemp;
        }
        GridJson += "]}";
        //  Rev_DBPublic.Rev_WriteLog.WriteLog("PubErrorLogPath", "ToDataGrid" + "123", GridJson);
        return GridJson;
    }
    #endregion

    #region DataTable转Json
    /// <summary>
    /// DataTable转Json for DataGrid
    /// </summary>
    /// <param name="_dt"></param>
    /// <returns></returns>
    public static string ToDataGridPage(DataTable _dt, int _row, int page, int records)
    {
        string GridJson = "{\"page\":" + page + ",\"total\":" + _row + ",\"records\":" + records + ",\"rows\":[";
        for (int i = ; i < _dt.Rows.Count; i++)
        {
            GridJson += "{";
            string strTemp = "";
            for (int j = ; j < _dt.Columns.Count; j++)
            {
                strTemp = (j == _dt.Columns.Count -  ? "" : ",");
                GridJson += "\"" + _dt.Columns[j].ColumnName.ToString() + "\":\"" + _dt.Rows[i][j].ToString() + "\"" + strTemp;
            }
            strTemp = (i == _dt.Rows.Count -  ? "}" : "},");
            GridJson += strTemp;
        }
        GridJson += "]}";
        //  Rev_DBPublic.Rev_WriteLog.WriteLog("PubErrorLogPath", "ToDataGrid" + "123", GridJson);
        return GridJson;
    }
    #endregion

    #region dataTable转换成Json格式
    /// <summary>
    /// dataTable转换成Json格式
    /// </summary>
    /// <param name="dt"></param>
    /// <returns></returns>
    public static string DataTable2Json(DataTable dt)
    {
        StringBuilder jsonBuilder = new StringBuilder();
        jsonBuilder.Append("[");
        for (int i = ; i < dt.Rows.Count; i++)
        {
            jsonBuilder.Append("{");
            for (int j = ; j < dt.Columns.Count; j++)
            {
                jsonBuilder.Append("\"");
                jsonBuilder.Append(dt.Columns[j].ColumnName);
                jsonBuilder.Append("\":\"");
                jsonBuilder.Append(dt.Rows[i][j].ToString());
                jsonBuilder.Append("\",");
            }
            jsonBuilder.Remove(jsonBuilder.Length - , );
            jsonBuilder.Append("},");
        }
        jsonBuilder.Remove(jsonBuilder.Length - , );
        if (dt.Rows.Count > )
        {
            jsonBuilder.Append("]");
        }
        return jsonBuilder.ToString();
    }

    #endregion dataTable转换成Json格式
}