1）在web.config 中system.web 节点下添加如下代码

 <pages controlRenderingCompatibilityVersion="4.0" clientIDMode="AutoID">
      <namespaces>
        <add namespace="MyMVC"/>
      </namespaces>
    </pages>
    <httpHandlers>
      <add path="*.cspx" verb="*" type="MyMVC.AjaxHandlerFactory,MyMVC" validate="true"/>
    </httpHandlers>

2）为了兼容IIs7.0 在<system.webServer>节点下添加如下代码：

 <validation validateIntegratedModeConfiguration="false"/>
    <security>
      <requestFiltering>
        <fileExtensions>
          <remove fileExtension=".cspx"/>
          <add fileExtension=".cspx" allowed="true"/>
        </fileExtensions>
      </requestFiltering>
    </security>
    <handlers>
      <add name="AjaxHandlerFactory" verb="*" path="*Ajax*/*.cspx"
                      type="MyMVC.AjaxHandlerFactory, MyMVC" preCondition="integratedMode"/>
    </handlers>

上边的是配置

例如在AjaxMenuManager.cs中有如下方法

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using MyMVC;
namespace Lesso.Invoicing.UI.AjaxMethod
{
    public class AjaxMenuManager
    {
        [Action]
        public string Test(string a)
        {
            return a;
        }
    }
}

在js中调用方法如下：

 $.ajax({
                url: "/Lesso.Invoicing.UI.AjaxMethod/AjaxMenuManager/Test.cspx",

              //Lesso.Invoicing.UI.AjaxMethod 命名空间；AjaxMenuManager 类名；Test 方法名
                data: { a: "2" },
                success: function (responseText) {
                    alert(responseText);
                },
                error: function (msg) {
                    alert(msg);
                }
            });

需要注意的是：

ajax方法的前缀为Ajax...

MyMVC 原创文章和源码下载地址：http://www.cnblogs.com/fish-li/archive/2012/02/12/2348395.html