前段时间我在Csdn上发表了一篇文章 VB2008使用.Net3.5扩展方法实现对象JSON序列化
至于如何将数据库的数据序列化成JSON，可以先创建实体类，然后把数据库的数据取出来写进实体类中，再参考上面文章的方法序列化成JSON
下面我演示的是另外一种方法
1、首先要创建一个数据库，上面有一张表，结构如下：
ID int PK，自增
Name varchar(50)
Email varchar(50)
Message varchar(50)
PostDate datetime getdate()
2、下载 ASP.NET Futures
3、创建一个WebApplication
4、添加对C:\Program Files\Microsoft ASP.NET\ASP.NET Futures July 2007\v1.2.61025\3.5\Microsoft.Web.Preview.dll的引用
5、修改Web.config增加以下配置节
<system.web.extensions>
<scripting>
<webServices>
<jsonSerialization>
<converters>
<add name="DataSetConverter" type="Microsoft.Web.Preview.Script.Serialization.Converters.DataSetConverter" />
<add name="DataRowConverter" type="Microsoft.Web.Preview.Script.Serialization.Converters.DataRowConverter" />
<add name="DataTableConverter" type="Microsoft.Web.Preview.Script.Serialization.Converters.DataTableConverter" />
</converters>
</jsonSerialization>
</webServices>
</scripting>
</system.web.extensions>
这样就能使.Net的数据对象与JSON序列化对应起来了
6、创建一个WebService，用于数据库操作
Imports System.Web.Services
Imports System.Web.Services.Protocols
Imports System.ComponentModel
Imports System.Data.SqlClient
Imports System.Web.Script.Services
' To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line.
<System.Web.Script.Services.ScriptService()> _
<System.Web.Services.WebService(Namespace:="http://lishewen.com.cn/")> _
<System.Web.Services.WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<ToolboxItem(False)> _
Public Class GuestBookService
Inherits System.Web.Services.WebService
Dim connstr As String = "Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\GuestBook.mdf;Integrated Security=True;User Instance=True"
'如果想序列化成XML可以把下面一行的注释去掉
'<ScriptMethod(ResponseFormat:=ResponseFormat.Xml)> _
<WebMethod()> _
Public Function GetMessages() As DataTable
Dim cmdstr = "SELECT * FROM [Message]"
Dim da As New SqlDataAdapter(cmdstr, connstr)
Dim dt As New DataTable("Message")
da.Fill(dt)
Return dt
End Function
End Class
上面程序的运行演示：http://webservice.lishewen.com.cn/guestbookservice.asmx
7、创建一个WebForm，测试用AJAX调用WebService
<%@ Page Language="vb" AutoEventWireup="false" CodeBehind="ASPXTest.aspx.vb" Inherits="LSWWebService.ASPXTest" %>
<!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>Untitled Page</title>
<script type="text/javascript">
function btnGetMessages_onclick()
{
LSWWebService.GuestBookService.GetMessages(onSucceeded);
}
function onSucceeded(result)
{
var idColName=result.columns[0].name;
var nameColName=result.columns[1].name;
var emailColName=result.columns[2].name;
var messageColName=result.columns[3].name;
var postdateColName=result.columns[4].name;
var rows=result.rows;
var builder=new Sys.StringBuilder("<table border=1>");
builder.append(String.format("<tr><th>{0}</th><th>{1}</th><th>{2}</th><th>{3}</th><th>{4}</th></tr>",idColName,nameColName,emailColName,messageColName,postdateColName));
for(var i=0;i<rows.length;++i)
{
builder.append(String.format("<tr><td>{0}</td><td>{1}</td><td>{2}</td><td>{3}</td><td>{4}</td></tr>",rows[i][idColName],rows[i][nameColName],rows[i][emailColName],rows[i][messageColName],rows[i][postdateColName]));
}
builder.append("</table>");
$get("result").innerHTML=builder.toString();
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ScriptManager ID="ScriptManager1" runat="server">
<Services>
<asp:ServiceReference Path="~/GuestBookService.asmx" />
</Services>
</asp:ScriptManager>
<input id="btnGetMessages" type="button" value="Get Messages" onclick="return btnGetMessages_onclick()" /></div>
<div id="result">
</div>
</form>
</body>
</html>
上面程序的运行演示：http://webservice.lishewen.com.cn/aspxtest.aspx
文章的相关源代码下载：lswwebservice.rar (4.75 kb)
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