jquery ajax学习

http://hi.baidu.com/cxzhang/blog/item/0166563892cc65fbb211c7b0.html.
http://topic.csdn.net/t/20030527/22/1842509.html
using System;
using System.Data;
using System.Text;
using System.Collections.Generic;
using System.Reflection;
public class ToJson
{
    /// <summary>
    /// datatable to json
    /// </summary>
    /// <param name="dt"></param>
    /// <returns></returns>
    public static string DataTableToJson(DataTable dt)
    {      
        StringBuilder JsonString = new StringBuilder();
       if (dt != null && dt.Rows.Count > 0)
        {
         
            JsonString.Append("[ ");
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                JsonString.Append("{ ");
                for (int j = 0; j < dt.Columns.Count; j++)
                {
                    if (j ==0)
                    {
                        JsonString.Append("\"" + dt.Columns[j].ColumnName.ToString() + "\":" + "\"" + dt