不当之处，欢迎指正。
我先把例子中的核心代码列出，方便大家阅读。
HelloWorldService服务中：
[WebMethod(EnableSession = true)] public string HelloWorld(string name)
{
String aaa = Session["name"].ToString(); string hello = String.IsNullOrEmpty(name) ? "无名氏" : name; hello += "你好,当前服务器时间是："; hello += DateTime.Now.ToUniversalTime() + " " + aaa; return hello;
}HelloWorld.aspx文件:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="HelloWorld.aspx.cs" Inherits="_Default" %><%@ Register Assembly="Microsoft.Web.Extensions" Namespace="Microsoft.Web.UI" TagPrefix="asp" %><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html><head id="Head1" runat="server"> <title>Hello</title><script type="text/javascript"> function SayHello() { var fs = HelloWorldService; fs.set_defaultSucceededCallback(OnShow); fs.HelloWorld(document.getElementById("name").value); } function OnShow(result) { var s = document.getElementById("result"); s.innerText = result; }</script> </head><body style="font-size: 12pt"> <form id="form1" runat="server"> <asp:ScriptManager ID="ScriptManager1" runat="server"> <Services> <asp:ServiceReference Path="~/HelloWorldService.asmx" /> </Services> </asp:ScriptManager> <div> 你的名字: <input type="text" maxlength="20" id="name" /> <input type="button" id="button1" value="问候" onclick="SayHello()" /> <div id="result"></div> </div> </form> </body></html>后台调用机制分析：(都是Microsoft.Web.Extensions.dll反编译后看到的)
1、在AssemblyInfo.cs中声明了如下一些javascript脚本：
[assembly: System.Web.UI.WebResource("Microsoft.Web.Resources.Timer.bmp", "image/bmp")]
[assembly: System.Web.UI.WebResource("Microsoft.Web.Resources.Background.gif", "image/gif")]
[assembly: System.Web.UI.WebResource("Microsoft.Web.Resources.ScriptLibrary.MicrosoftAjaxWebForms.debug.js", "application/x-javascript")]
[assembly: System.Web.UI.WebResource("Microsoft.Web.Resources.ScriptLibrary.MicrosoftAjaxRuntime.debug.js", "application/x-javascript")]
[assembly: System.Web.UI.WebResource("Microsoft.Web.Resources.ScriptLibrary.MicrosoftAjax.debug.js", "application/x-javascript")]
[assembly: System.Web.UI.WebResource("Microsoft.Web.Resources.ScriptLibrary.MicrosoftAjaxWebForms.js", "application/x-javascript")]
[assembly: System.Web.UI.WebResource("Microsoft.Web.Resources.ScriptLibrary.MicrosoftAjaxRuntime.js", "application/x-javascript")]
[assembly: System.Web.UI.WebResource("Microsoft.Web.Resources.ScriptLibrary.MicrosoftAjax.js", "application/x-javascript")]
这些javascript脚本也都是作为资源包含在Microsoft.Web.Extensions.dll中的
2、在ScriptManager的OnPreRender中进行如下操作，进行js代码的注册(有的方法是调用其它类里面的)：
//取得AJax的客户端脚本名称 private static string GetFullName(string name, System.Reflection.Assembly assembly) { if (assembly != ScriptReference.AtlasFrameworkAssembly)
{ return name;
} return ("Microsoft.Web.Resources.ScriptLibrary." + name); } //取得dll中js文件的位置 string IClientScriptManager.GetWebResourceUrl(Type type, string resourceName) { return this._clientScriptManager.GetWebResourceUrl(type, resourceName); } //注册客户段脚本(写入页面的html文件中去) void IClientScriptManager.RegisterClientScriptInclude(Type type, string key, string url) { this._clientScriptManager.RegisterClientScriptInclude(type, key, url); } //注册服务 //取得页面上有哪些服务，如上面的HelloWorldService.asmx服务,然后调用如下语句 this._clientScriptManager.RegisterClientScriptInclude(type, "HelloWorldService.asmx/jsdebug", "HelloWorldService.asmx/jsdebug");以上主要是使用.net 2.0新增的ClientScriptManager类进行客户端脚本的注册，也就是生成我们在页面上看到的如下一段代码：
(通过查看运行时的aspx文件的html代码)
<script src="/Web/WebResource.axd?d=7lZSau3voGpyPgiEEMwJxQ2&t=632965017419375000" type="text/javascript"></script>
......
<script src="/Web/WebResource.axd?d=VbevhO3ptb2WYvwQWrgTHKAWH4jfDIInCsIvYHSSJgRDZKhi9uLV9U_0kyOUMuNB32yLgf_UUzCml8vnGl7OI4r89qpFWhjBi2BmMZGBkApjwmG5MAGWzA_yjFYvRA8w2gdgDWR5RgcQF-F7MVigcyaKFVde2W9oIqW8P4zdL9g1&t=632985966674218750" type="text/javascript"></script>
<script src="HelloWorldService.asmx/jsdebug" type="text/javascript"></script>
3、通过IHttpHandlerFactory接口对服务进行处理：
在web.config中进行注册：
<httpHandlers>
<remove verb="*" path="*.asmx"/>
<add verb="*" path="*.asmx" validate="false" type="Microsoft.Web.Script.Services.ScriptHandlerFactory, Microsoft.Web.Extensions"/>
</httpHandlers>
然后在ScriptHandlerFactory中调用如下一段代码：
public void ProcessRequest(HttpContext context) { this._originalHandler.ProcessRequest(context); } base._builder.Append(text1).Append(".set_path = function(value) { \r\n/// <summary>Sets the service url.</summary>\r\n/// <param name=\"path\" type=\"String\">The service url.\r\nvar e = Function._validateParams(arguments, [{name: 'path', type: String}]); if (e) throw e; ").Append(text1).Append("._staticInstance._path = value; }\r\n"); base._builder.Append(text1).Append(".get_path = function() { \r\n/// <summary>Returns the service url.</summary>\r\n/// <returns type=\"String\">The service url.</returns>\r\nreturn ").Append(text1).Append("._staticInstance._path; }\r\n"); base._builder.Append(text1).Append(".set_timeout = function(value) { \r\n/// <summary>Sets the service timeout.</summary>\r\n/// <param name=\"value\" type=\"Number\">The service timeout.\r\nvar e = Function._validateParams(arguments, [{name: 'timeout', type: Number}]); if (e) throw e; if (value < 0) { throw Error.argumentOutOfRange('value', value, Sys.Res.invalidTimeout); }\r\n").Append(text1).Append("._staticInstance._timeout = value; }\r\n"); base._builder.Append(text1).Append(".get_timeout = function() { \r\n/// <summary>Returns the service timeout.</summary>\r\n/// <returns type=\"Number\">The service timeout.</returns>\r\nreturn ").Append(text1).Append("._staticInstance._timeout; }\r\n"); base._builder.Append(text1).Append(".set_defaultUserContext = function(value) { \r\n/// <summary>Sets the service default userContext.</summary>\r\n/// <param name=\"value\">The service default user context.\r\n").Append(text1).Append("._staticInstance._userContext = value; }\r\n"); base._builder.Append(text1).Append(".get_defaultUserContext = function() { \r\n/// <summary>Returns the service default user context.</summary>\r\n/// <returns>The service default user context.</returns>\r\nreturn ").Append(text1).Append("._staticInstance._userContext; }\r\n"); base._builder.Append(text1).Append(".set_defaultSucceededCallback = function(value) { \r\n/// <summary>Sets the service default succeeded callback.</summary>\r\n/// <param name=\"value\" type=\"Function\">The service default succeed callback function.\r\nvar e = Function._validateParams(arguments, [{name: 'defaultSucceededCallback', type: Function}]); if (e) throw e; ").Append(text1).Append("._staticInstance._succeeded = value; }\r\n"); base._builder.Append(text1).Append(".get_defaultSucceededCallback = function() { \r\n/// <summary>Returns the service default succeeded callback.</summary>\r\n/// <returns type=\"Function\">The service default succeeded callback.</returns>\r\nreturn ").Append(text1).Append("._staticInstance._succeeded; }\r\n"); base._builder.Append(text1).Append(".set_defaultFailedCallback = function(value) { \r\n/// <summary>Sets the service default failed callback function.</summary>\r\n/// <param name=\"value\" type=\"Function\">The service default failed callback function.\r\nvar e = Function._validateParams(arguments, [{name: 'defaultFailedCallback', type: Function}]); if (e) throw e; ").Append(text1).Append("._staticInstance._failed = value; }\r\n"); base._builder.Append(text1).Append(".get_defaultFailedCallback = function() { \r\n/// <summary>Returns the service default failed callback function.</summary>\r\n/// <returns type=\"Function\">The service default failed callback function.</returns>\r\nreturn ").Append(text1).Append("._staticInstance._failed; }\r\n"); .. context.Response.ContentType = "application/x-javascript"; context.Response.Write(text1);以上代码实际上就是根据页面上有的服务生成对应的javascript代码，比如我们针对上面的HelloWorldService.asmx服务，就会生成如下一段javascript
代码，注册到页面中去：
var HelloWorldService=function() {
this._timeout = 0;
this._userContext = null;
this._succeeded = null;
this._failed = null;
}
HelloWorldService.prototype={
HelloWorld:function(name,succeededCallback, failedCallback, userContext) {
/// <summary>Invoke the HelloWorld WebMethod</summary>
/// <param name=\"name\">WebMethod parameter: name(type: String)</param>
/// <param name=\"succeededCallback\" type=\"function\" optional=\"true\">Callback on successful completion of request</param>
/// <param name=\"failedCallback\" type=\"function\" optional=\"true\">Callback on failure of request</param>
/// <param name=\"userContext\" optional=\"true\">User context data (any JavaScript type)</param>
return Sys.Net._WebMethod._invoke.apply(null, [ this, 'HelloWorld','HelloWorldService.HelloWorld',false,{name:name},succeededCallback, failedCallback, userContext]); },_get_path: function() { return HelloWorldService.get_path(); },
set_timeout: function(value) {
/// <summary>Sets the timeout for this service.</summary>
/// <param name=\"value\" type=\"Number\">The timeout in milliseconds.</param>
var e = Function._validateParams(arguments, [{name: 'timeout', type: Number}]);
if (e) throw e;
if (value < 0) {
throw Error.argumentOutOfRange('value', value, Sys.Res.invalidTimeout);
}
this._timeout = value;
},
get_timeout: function() {
/// <summary>Returns the timeout in milliseconds for this service.</summary>
/// <returns type=\"Number\">The timeout in milliseconds for the service.</returns>
return this._timeout;
},
set_defaultUserContext: function(value) {
/// <summary>Sets the default userContext for this service.</summary>
/// <param name=\"value\">The default userContext for this service.</param>
this._userContext = value;
},
get_defaultUserContext: function() {
/// <summary>Returns the default userContext for this service.</summary>
/// <returns>Returns the default userContext for this service.</returns>
return this._userContext;
},
set_defaultSucceededCallback: function(value) {
/// <summary>Sets the default succeededCallback for this service.</summary>
/// <param name=\"value\" type=\"Function\">The default succeededCallback for this service.</param>
var e = Function._validateParams(arguments, [{name: 'defaultSucceededCallback', type: Function}]);
if (e) throw e;
this._succeeded = value;
},
get_defaultSucceededCallback: function() {
/// <summary>Returns the default succeededCallback for this service.</summary>
/// <returns type=\"Function\">Returns the default succeededCallback for this service.</returns>
return this._succeeded;
},
set_defaultFailedCallback: function(value) {
/// <summary>Sets the default FailedCallback for this service.</summary>
/// <param name=\"value\" type=\"Function\">The default FailedCallback for this service.</param>
var e = Function._validateParams(arguments, [{name: 'set_defaultFailedCallback', type: Function}]);
if (e) throw e;
this._failed = value;
},
get_defaultFailedCallback: function() {
/// <summary>Returns the default failedCallback for this service.</summary>
/// <returns type=\"Function\">Returns the default failedCallback for this service.</returns>
return this._failed;
}
}
HelloWorldService._staticInstance = new HelloWorldService();
HelloWorldService.set_path = function(value) {
/// <summary>Sets the service url.</summary>
/// <param name=\"path\" type=\"String\">The service url.
var e = Function._validateParams(arguments, [{name: 'path', type: String}]); if (e) throw e; HelloWorldService._staticInstance._path = value; }
HelloWorldService.get_path = function() {
/// <summary>Returns the service url.</summary>
/// <returns type=\"String\">The service url.</returns>
return HelloWorldService._staticInstance._path; }
HelloWorldService.set_timeout = function(value) {
/// <summary>Sets the service timeout.</summary>
/// <param name=\"value\" type=\"Number\">The service timeout.
var e = Function._validateParams(arguments, [{name: 'timeout', type: Number}]); if (e) throw e; if (value < 0) { throw Error.argumentOutOfRange('value', value, Sys.Res.invalidTimeout); }
HelloWorldService._staticInstance._timeout = value; }
HelloWorldService.get_timeout = function() {
/// <summary>Returns the service timeout.</summary>
/// <returns type=\"Number\">The service timeout.</returns>
return HelloWorldService._staticInstance._timeout; }
HelloWorldService.set_defaultUserContext = function(value) {
/// <summary>Sets the service default userContext.</summary>
/// <param name=\"value\">The service default user context.
HelloWorldService._staticInstance._userContext = value; }
HelloWorldService.get_defaultUserContext = function() {
/// <summary>Returns the service default user context.</summary>
/// <returns>The service default user context.</returns>
return HelloWorldService._staticInstance._userContext; }
HelloWorldService.set_defaultSucceededCallback = function(value) {
/// <summary>Sets the service default succeeded callback.</summary>
/// <param name=\"value\" type=\"Function\">The service default succeed callback function.
var e = Function._validateParams(arguments, [{name: 'defaultSucceededCallback', type: Function}]); if (e) throw e; HelloWorldService._staticInstance._succeeded = value; }
HelloWorldService.get_defaultSucceededCallback = function() {
/// <summary>Returns the service default succeeded callback.</summary>
/// <returns type=\"Function\">The service default succeeded callback.</returns>
return HelloWorldService._staticInstance._succeeded; }
HelloWorldService.set_defaultFailedCallback = function(value) {
/// <summary>Sets the service default failed callback function.</summary>
/// <param name=\"value\" type=\"Function\">The service default failed callback function.
var e = Function._validateParams(arguments, [{name: 'defaultFailedCallback', type: Function}]); if (e) throw e; HelloWorldService._staticInstance._failed = value; }
HelloWorldService.get_defaultFailedCallback = function() {
/// <summary>Returns the service default failed callback function.</summary>
/// <returns type=\"Function\">The service default failed callback function.</returns>
return HelloWorldService._staticInstance._failed; }
HelloWorldService.set_path(\"/Web/HelloWorldService.asmx\");
HelloWorldService.HelloWorld= function(name,onSuccess,onFailed,userContext) { /// <summary>Invoke the HelloWorld WebMethod</summary>
/// <param name=\"name\">WebMethod parameter: name(type: String)</param>
/// <param name=\"succeededCallback\" type=\"function\" optional=\"true\">Callback on successful completion of request</param>
/// <param name=\"failedCallback\" type=\"function\" optional=\"true\">Callback on failure of request</param>
/// <param name=\"userContext\" optional=\"true\">User context data (any JavaScript type)</param>
HelloWorldService._staticInstance.HelloWorld(name,onSuccess,onFailed,userContext); }
4、实际调用
这样服务注册好之后，我们在页面上写的
var fs = HelloWorldService;
fs.set_defaultSucceededCallback(OnShow);
fs.HelloWorld(document.getElementById("name").value);
实际上就是调用注册好的javascript脚本，然后这些脚本再通过通用的AJAX连接XML的异步方式调用后台代码就可以了