Ext.NET，这个名字可能有些许陌生，但说起ExtJS和Coolite大家应该是相当熟悉的。其实Ext.NET原名Coolite，是Coolite发展到1.0版本后对该产品的重新命名。Ext.NET是基于.NET Framework 3.5的一套支持ASP.NET AJAX的Web控件，它基于跨浏览器的ExtJS 库开发而来并简化了开发步骤，包含有丰富的Ajax运用。
Ext.NET是开源的。由于Ext.NET基于ExtJS的缘故，所以不可避免会有类似ExtJS控件运行又大又慢的毛病，但因为它界面美观，减少了很多美工的精力，你就可以省掉一大串的js代码，界面完全可以用Ext.NET简单配置就得到很炫的页面效果，使程序员可以专注于后台代码的编写。而且Ext.Net的Ajax+Json操作简单方便，因此作为企业应用是相当不错的选择。
Ext.NET是一组开源的Asp.net(WebForm,MVC)组件。基于Ext.Js库开发，含有100多个工具，如TextBox,Combox，Button，ToolBar，StateBar，Panel，TabPanel，ExplorerBar,MenuBar,PictureBox 等多种控件并支持Ajax无刷新效果。
下载地址：http://www.ext.net/download/
示例地址：http://examples.ext.net/
环境：VS2005+、服务器.NET Framework3.5+、网站系统.net 2.0+
Ext.NET最大不足：还是开发阶段，存在不少BUG。
Ext.Net特点：
1.多种控件。能快速的创建高视觉的用户界面
2.300多个示例，能让你快速上手
3.丰富的Ext.js API提供支持
4开源闭源双协议
Ext.NET配置方法：
1.从官方网站下载Ext.NET：(现版本为Coolite 0.8.2，Ext.NET1.0为Beta版尚未开放下载)
http://www.coolite.com/download/
2.项目中引用
在项目点击引用，通过浏览增加Ext.NET.dll、Ext.NET.Utilities.dll引用。
3.工具箱增加
在工具箱增加Tab Ext.NET。增加文件:Ext.NET.dll。
4.修改Web.config文件，如下设置
<?xml version="1.0"?><configuration>
<configSections>
<sectionGroup type="System.Web.Configuration.SystemWebExtensionsSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
<sectionGroup type="System.Web.Configuration.ScriptingSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
<section type="System.Web.Configuration.ScriptingScriptResourceHandlerSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
<sectionGroup type="System.Web.Configuration.ScriptingWebServicesSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
<section type="System.Web.Configuration.ScriptingJsonSerializationSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="Everywhere"/>
<section type="System.Web.Configuration.ScriptingProfileServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
<section type="System.Web.Configuration.ScriptingAuthenticationServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
<section type="System.Web.Configuration.ScriptingRoleServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
</sectionGroup>
</sectionGroup>
</sectionGroup>
</configSections>
<appSettings/>
<connectionStrings/>
<system.web>
<!--
Set compilation debug="true" to insert debugging
symbols into the compiled page. Because this
affects performance, set this value to true only
during development.
-->
<compilation debug="false">
<assemblies>
<add assembly="System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B< XMLNAMESPACE PREFIX ="ST1" />77A5C561934E089"/>
<add assembly="System.Data.DataSetExtensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
<add assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add assembly="System.Xml.Linq, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
<add assembly="System.Design, Version=2.0.0.0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/></assemblies>
</compilation>
<!--
The <authentication> section enables configuration
of the security authentication mode used by
ASP.NET to identify an incoming user.
-->
<authentication mode="Windows"/>
<!--
The <customErrors> section enables configuration
of what to do if/when an unhandled error occurs
during the execution of a request. Specifically,
it enables developers to configure html error pages
to be displayed in place of a error stack trace.
<customErrors mode="RemoteOnly" defaultRedirect="GenericErrorPage.htm">
<error statusCode="403" redirect="NoAccess.htm" />
<error statusCode="404" redirect="FileNotFound.htm" />
</customErrors>
-->
<pages>
<controls>
<add tagPrefix="asp" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add tagPrefix="asp" namespace="System.Web.UI.WebControls" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
</controls>
</pages>
<httpHandlers>
<remove verb="*" path="*.asmx"/>
<add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" validate="false"/>
</httpHandlers>
<httpModules>
<add type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add type="Ext.Net.DirectRequestModule, Ext.Net" />
</httpModules>
</system.web>
<system.codedom>
<compilers>
<compiler language="c#;cs;csharp" extension=".cs" warningLevel="4" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
<providerOption value="v3.5"/>
<providerOption value="false"/>
</compiler>
</compilers>
</system.codedom>
<!--
The system.webServer section is required for running ASP.NET AJAX under Internet
Information Services 7.0. It is not necessary for previous version of IIS.
-->
<system.webServer>
<validation validateIntegratedModeConfiguration="false"/>
<modules>
<remove />
<add preCondition="managedHandler" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
</modules>
<handlers>
<remove />
<remove />
<remove />
<remove />
<add verb="*" path="*.asmx" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add verb="*" path="*_AppService.axd" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
<add preCondition="integratedMode" verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
</handlers>
</system.webServer>
<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity publicKeyToken="31bf3856ad364e35"/>
<bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="3.5.0.0"/>
</dependentAssembly>
<dependentAssembly>
<assemblyIdentity publicKeyToken="31bf3856ad364e35"/>
<bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="3.5.0.0"/>
</dependentAssembly>
</assemblyBinding>
</runtime>
</configuration>5.在页面中添加Ext.NET引用
<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>
6.在使用Ext.NET控件时必须注意，添加任意控件之前必须添加ResourceManager控件
<ext:ResourceManager runat="server">
完成配置之后，就让我们准备开始奇妙的Ext.NET之旅吧！