ASP.NET - JQuery的.getJSON给Dropdownlist绑定Item

http://www.cnblogs.com/Mac_Hui/archive/2010/07/27/1785864.html

1、首先建立以个.ashx文件（Generic Handler）,在此文件中生成JSON数据。

using System;
using System.Web;
using System.Data;
using System.Text;

public class EmployeeLoad : IHttpHandler {

    public void ProcessRequest (HttpContext context) {

        StringBuilder sb = new StringBuilder();
        DataTable dt = new DataTable();
        dt = FetchEmployeeInfo().Tables[];
        if (dt == null)
            return;
        if (dt.Rows.Count == )
        {
            return;
        }
        else
        {
           sb.Append("[");
            for(int i=;i<dt.Rows.Count;i++)
           {
               sb.Append("{\"ID\":\"" + dt.Rows[i]["ID"].ToString() + "\",\"Name\":\"" + dt.Rows[i]["Name"].ToString() + "\",\"Age\":" + dt.Rows[i]["Age"].ToString() + ",\"Tel\":\"" + dt.Rows[i]["Tel"].ToString() + "\"},");
           }

            sb.Remove(sb.Length - , );
            sb.Append("]");
        }

        context.Response.ContentType = "application/json";
        context.Response.ContentEncoding = Encoding.UTF8;
        context.Response.Write(sb.ToString());
    }

    public bool IsReusable {
        get {
            return false;
        }
    }

    public DataSet FetchEmployeeInfo()
    {
        DataSet ds = new DataSet();
        DataTable dt = new DataTable();
        dt.Columns.Add("ID", typeof(string));
        dt.Columns.Add("Name", typeof(string));
        dt.Columns.Add("Age", typeof(int));
        dt.Columns.Add("Tel", typeof(string));

        //DataRow dr;

        DataRow dr = dt.NewRow();
        dr["ID"] = "";
        dr["Name"] = "Jim Hui";
        dr["Age"] = ;
        dr["Tel"] = "";
        dt.Rows.Add(dr);

        dr = dt.NewRow();
        dr["ID"] = "";
        dr["Name"] = "Kevin Lee";
        dr["Age"] = ;
        dr["Tel"] = "";
        dt.Rows.Add(dr);

        ds.Tables.Add(dt);
        return ds;

    }

}

2、其次在前台调用ashx文件中生成的数据

<script type="text/javascript" src="JavaScript/jquery-1.3.2.js"></script>
    <script language="javascript" type="text/javascript">
      $(document).ready(function(){
        BindDropDownList();
        });
        function  BindDropDownList()
        {
            $("#DropDownList1").html("");
            $.getJSON("EmployeeLoad.ashx",null,function(json){
            $.each(json,function(i){$("#DropDownList1").append($("<option></option>").val(json[i].ID).html(json[i].Name))});
            });
            $("<option></option>").val("").html("").appendTo("#DropDownList1");

        }
    </script>

这样就OK了。

注意：

1、要调试ashx代码，需要安装VS2005 SP1,即使有sp2也不可以的。

　　 2、Dropdownlist增加空白选项是：$("<option></option>").val("").html("").appendTo("#DropDownList1")；