关于asp.net的增删改查问题``菜鸟求解答~~谢谢！无法取到category的值，插入为空值

（1）html页面

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="Easyui.Default1" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <link href="Scripts/easyUI-1.3.2/themes/default/easyui.css" rel="stylesheet" type="text/css" />
    <link href="Scripts/easyUI-1.3.2/themes/icon.css" rel="stylesheet" type="text/css" />
    <script src="Scripts/jquery-1.4.1.min.js" type="text/javascript"></script>
    <script src="Scripts/easyUI-1.3.2/jquery.easyui.min.js" type="text/javascript"></script>
    <script src="Scripts/easyUI-1.3.2/locale/easyui-lang-zh_CN.js" type="text/javascript"></script>
    <script src="Scripts/common.js" type="text/javascript"></script>
</head>
<body>
    <div class="easyui-layout" style="width: 100%; height: 600px; text-align: center;">
        <div data-options="region:'north'" style="height: 50px">
            <input id="ss" />
            <div id="mm" style="width: 120px; height: 120px;">
                <div data-options="name:'allcategory',iconCls:'icon-ok'">
                    问题分类</div>
                <div data-options="name:'content'">
                    问题内容</div>
            </div>
            <input type="hidden" name="reqTypes" id="txt_editType" />
            <a onclick="addcategory()" class="easyui-linkbutton" data-options="iconCls:'icon-add'">
                增加问题分类</a> <a class="easyui-linkbutton" data-options="iconCls:'icon-delete'">删除问题分类</a>
            <a class="easyui-linkbutton" data-options="iconCls:'icon-cut'">修改问题分类</a>
        </div>
        <div data-options="region:'west',split:true" title="问题分类" style="width: 200px;">
        <ul id="tt"></ul>
          </div>   
        <div data-options="region:'center',title:'Main Title',iconCls:'icon-ok'">
        </div>
    </div>
    <form id="addcategory" style="display: none;" action="">
    <div id="dd" style="text-align: center;">
        <label>
            请输入问题类别</label>
        <input id="txtCategoryName" name="categoryname" type="text" style="width: 150px" />
    </div>
    </form>
</body>
</html>

 

（2）js代码

function addcategory() {
    $("#dd").dialog({
        closable: false, //右上角的关闭按钮，因为dialog框架关联的是window框架，window框架关联的是panel框架
        title: '添加问题分类', //dialog左上角的名称
        modal: true, //模式化
        width: 200,
        height: 200,
        buttons: [{ //dialog右下角的按钮，
            text: '保存', //按钮名称
            iconCls: 'icon-add', //按钮左侧显示的图片
            handler: function () {//按钮点击之后出发的方法
                alert($("#txtCategoryName").val());
//                alert("category");
                $("#txtCategoryName").val('');
                var category = $("#txtCategoryName").val();
                $.post('/ashx/UserHandler.ashx?action=add ', { category: 'category' },
                      function (res) {
                          if (res == 1) {//插入成功
                              $("#txtCategoryName").val('');
                              $("#dd").dialog("close"); //关闭该dialog
                              $.messager.show({//浏览器右下角弹框，
                                  title: '提示',
                                  msg: '恭喜您，插入数据成功！',
                                  timeout: 5000, //弹框保留时间
                                  showType: 'slide'//展示样式
                              });
                          }
                          else {//插入数据失败
                              $.messager.show({
                                  title: '提示',
                                  msg: '插入数据失败',
                                  timeout: 5000, //弹框保留时间
                                  showType: 'slide'//展示样式             
                              });
                          }
                      }
                   )
            }
        }]
    });

 

（3）一般处理程序代码

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

namespace Easyui.ashx
{
    /// <summary>
    /// UserHandler 的摘要说明
    /// </summary>
    public class UserHandler : IHttpHandler
    {
        private HttpContext context;
        private DAL.SQLHelper sqlhelper = new DAL.SQLHelper();
        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";
            //context.Response.Write("Hello World");


            string action = context.Request["action"];
            if (string.IsNullOrEmpty(action))
            {
                context.Response.Write("参数错误");
                return;
            }
            this.context = context;
            switch (action.ToLower())
            {
                case "add":
                    Add();
                    break;
                //case "delete":
                //    Deleted();
            }



        }

        public int Add()
        {
            int res;
            string category = context.Request["category"];
            string sqlStr = @"insert into Category(CategoryName) values(@category)";
            SqlParameter[] parameters = { new SqlParameter("@category", category) };
            res = sqlhelper.ExecuteNonQuery(sqlStr, parameters, CommandType.Text);
            return res;
        }




        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

其中category一直取到为空值~~~希望知道！！调试时候看到res也是1 ，为何插入的为空值！！菜鸟求指导！！感谢@@@@