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asp.net中使用jquery+ashx 做ajax,json做数据传输

一直在想在asp.net中怎么才能向在java中那样用struts那样做页面请求。

当然asp.net mvc就是类似struts的东西吧，不过还没来得及学习。

今天就用ashx来接收页面请求，并调用后台，然后返回数据给前台，用jquer .ajax提交请求，接收ashx返回的数据。

例子：

例子是要实现页面加载时从数据库读取数据，并把数据放到一个下拉列表中。（因为是用ajax，就建html页面就行了，一直不喜欢aspx页面，感觉它太臃肿了。）

一.准备工作：

1.建web应用程序aspnetAjax

2.建index.htm

3.建个js文件夹，把jquery.js放进去，

4.建ajax文件夹，里面放ashx

5.在js文件夹建index.js，一般我们都是一个页面对应一个js

6.在ajax文件夹，建IndexHandler.ashx，一般一个js页面对应一个一般用户控件，这样层次感很强，也很好维护。

二.html页面

html页面就简单了，我们要用ajax读后台做个下拉列表，所以页面就放个DIV就行了。其他的交给js.

<!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>
    <title>测试</title>
 
    <script src="js/jquery-1.2.3-intellisense.js" type="text/javascript"></script>
 
    <script src="js/index.js" type="text/javascript"></script>
 
</head>
<body>
    企业性质<div id="vocaspec"> </div>
    行业类型<div id="industr"> </div>　　　　　　
</body>
</html>

编写IndexHandler.ashx代码

namespace aspnetAjax.ajax
{
    /// <summary>
    /// $codebehindclassname$ 的摘要说明
    /// </summary>
 
    public class IndexHandler : IHttpHandler
    {
 
        public void ProcessRequest(HttpContext context)
        {
           context.Response.ContentType = "application/json";
           //接收提交过来的meth参数
            string meth = context.Request.Params["meth"].ToString(); 
            //根据参数调用不同的方法
            switch (meth) 
            {
                case "load":
                    loadjson(context);
                    break;
                case "add":
                    add(context);
                    break;
            }        
       }
 
        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
 
       //页面加载方法，调用BLL，获得数据
         private void loadjson(HttpContext context) 
        {
            //实例BLL
            VocaSpecSortBLL vocaSpec = new VocaSpecSortBLL();
            BLL.Owner ownerbll = new GYXMGL.BLL.Owner();
              
             DataSet ds = vocaSpec.GetList("");
             DataSet dsindustr = ownerbll.Getcharcte();
 
             //实例一个StringBuilder 用来拼接一个json数据
             StringBuilder sbvoca = new StringBuilder();
 
            if (ds != null && ds.Tables[0].Rows.Count > 0)
            {
                sbvoca.Append("{\"voce\":[");
                int i = 1;
                int count = ds.Tables[0].Rows.Count;
                foreach (DataRow dr in ds.Tables[0].Rows) 
                {
                    if (i == count)
                    {
                        sbvoca.Append("{\"code\":\"" + dr[0] + "\",\"name\":\"" + dr[1] + "\"}");
                    }
                    else
                    {
                        sbvoca.Append("{\"code\":\"" + dr[0] + "\",\"name\":\"" + dr[1] + "\"},");
                    }
                    i++;
                }
                sbvoca.Append("]");
            }
            if (dsindustr != null && dsindustr.Tables[0].Rows.Count > 0) 
            {
 
                sbvoca.Append(",\"industr\":[");
                int i = 1;
                int count = dsindustr.Tables[0].Rows.Count;
                foreach (DataRow dr in dsindustr.Tables[0].Rows)
                {
                    if (i == count)
                    {
                        sbvoca.Append("{\"code\":\"" + dr[0] + "\",\"name\":\"" + dr[1] + "\"}");
                    }
                    else
                    {
                        sbvoca.Append("{\"code\":\"" + dr[0] + "\",\"name\":\"" + dr[1] + "\"},");
                    }
                    i++;
                }
                sbvoca.Append("]");
            }
            sbvoca.Append("}");
            context.Response.Write(sbvoca.ToString());
             
            context.Response.End();
        }
 
    }
}

我们把index.js改下

$(document).ready(function() {
    $.ajax({
        type: "POST",
        url: "../ajax/NewOwnerHandler.ashx",
        //我们用text格式接收
        dataType: "text",
        data: "meth=load",
        success: function(msg) {
            alert(msg);
            //显示后台数据
            $("#vocaspec").html(msg);
            // $("#industr").html(industr);
        }
    });
});

显示在下拉列表中。就要遍历json中的数组。

{
"voce":[{"code":"1","name":"农林水利"},{"code":"10","name":"军工"},{"code":"11","name":"农林"},{"code":"12","name":"水利(电)"},{"code":"13","name":"水电站"},{"code":"14","name":"输变线"},{"code":"15","name":"煤矿"},{"code":"16","name":"气田"},{"code":"17","name":"公路"},{"code":"18","name":"铁路"},{"code":"19","name":"民航"},{"code":"2","name":"能源"},{"code":"20","name":"信息产业"},{"code":"21","name":"化工"},{"code":"22","name":"机械"},{"code":"23","name":"冶金"},{"code":"24","name":"有色金属"},{"code":"25","name":"建材"},{"code":"26","name":"医药"},{"code":"27","name":"轻工"},{"code":"28","name":"农牧产品深加工"},{"code":"3","name":"交通"},{"code":"4","name":"通讯"},{"code":"5","name":"特色产业"},{"code":"6","name":"城市基础设施"},{"code":"7","name":"商贸流通"},{"code":"8","name":"旅游"},{"code":"9","name":"文体卫"}],
"industr":[{"code":"1","name":"国有"},{"code":"2","name":"私人"}]
}

修改index.js代码，遍历json数据把数据显示成下拉列表

$(document).ready(function() {
    $.ajax({
        type: "POST",
        url: "../ajax/NewOwnerHandler.ashx",
        //json格式接收数据
        dataType: "json",
        //指点后台调用什么方法
        data: "meth=load",
 
        success: function(msg) {
             //实例2个字符串变量来拼接下拉列表
               var industr = "<select name=\"industr\"><option label=\"---请选择---\"></option>";
               var vocaspec = "<select name=\"vocaspec\"><option label=\"---请选择---\"></option>";
              //使用jquery解析json中的数据
               $.each(msg.voce, function(n, value) {
                     vocaspec += ("<option value=\"" + value.code + "\" label=\"" + value.name + "\">");
                     vocaspec += ("</option>");
                    });
                $.each(msg.industr, function(n, value) {
                     industr += ("<option value=\"" + value.code + "\" label=\"" + value.name + "\">");
                      industr += ("</option>");
                   });
             industr += ("</select>");
 
             $("#vocaspec").html(vocaspec);
            $("#industr").html(industr);
        }
    });
});