【正文】 age with the content from the content page. All code is piled, which enables strong typing, performance optimizations, and early binding, among other benefits. Once the code has been piled, the mon language runtime further piles code to native code, providing improved performance. includes a piler that will pile all your application ponents including pages and controls into an assembly that the hosting environment can then use to service user requests. In addition to the security features of .NET, provides an advanced security infrastructure for authenticating and authorizing user access as well as performing other securityrelated tasks. You can authenticate users using Windows authentication supplied by IIS, or you can manage authentication using your own user database using forms authentication and membership. Additionally, you can manage the authorization to the capabilities and information of your Web application using Windows groups or your own custom role database using roles. You can easily remove, add to, or replace these schemes depending upon the needs of your application. always runs with a particular Windows identity so you can secure your application using Windows capabilities such as NTFS Access Control Lists (ACLs), database permissions, and so on. For more information on the identity of , provides intrinsic state management functionality that enables you to store information between page requests, such as customer information or the contents of a shopping cart. You can save and manage applicationspecific, sessionspecific, pagespecific, userspecific, and developerdefined information. This information can be independent of any controls on the page. offers distributed state facilities, which enable you to manage state information across multiple instances of the same application on one puter or on several puters. applications use a configuration system that enables you to define configuration settings for your Web server, for a Web site, or for individual applications. You can make configuration settings at the time your applications are deployed and can add or revise configuration settings at any time with minimal impact on operational Web applications and servers. configuration settings are stored in XMLbased files. Because these XML files are ASCII text files, it is simple to make configuration changes to your Web applications. You can extend the configuration scheme to suit your requirements. includes features that enable you to monitor health and performance of your application. health monitoring enables reporting of key events that provide information about the health of an application and about error conditions. These events show a bination of diagnostics and monitoring characteristics and offer a high degree of flexibility in terms of what is logged and how it is logged. supports two groups of performance counters accessible to your applications:The system performance counter groupThe application performance counter group takes advantage of the runtime debugging infrastructure to provide crosslanguage and crossputer debugging support. You can debug both managed and unmanaged objects, as well as all languages supported by the mon language runtime and script languages. In addition, the page framework provides a trace mode that enables you to insert instrumentation messages into your Web pages. supports XML Web services. An XML Web service is a ponent containing business functionality that enables applications to exchange information across firewalls using standards like HTTP and XML messaging. XML Web services are not tied to a particular ponent technology or objectcalling convention. As a result, programs written in any language, using any ponent model, and running on any operating system can access XML Web services. includes an extensible hosting environment that controls the life cycle of an application from when a user first accesses a resource (such as a page) in the application to the point at which the application is shut down. While relies on a Web server (IIS) as an application host, provides much of the hosting functionality itself. The architecture of enables you to respond to application events and create custom HTTP handlers and HTTP modules. includes enhanced support for creating designers for Web server controls for use with a visual design tool such as Visual Studio. Designers enable you to build a designtime user interface for a control, so that developers can configure your control39。s properties and content in the visual design tool. Introduction to the C Language and the .NET Framework C is an elegant and typesafe objectoriented language that enables developers to build a wide range of secure and robust applications that run on the .NET Framework. You can use C to create traditional Windows client applications, XML Web services, distributed ponents, clientserver applications, database applications, and much, much more. Microsoft Visual C 2005 provides an advanced code editor, convenient user interface designers, integrated debugger, and many other tools to facilitate rapid application development based on version of the C language and the .NET Framework.The Visual C documentation assumes that you have an understanding of basic programming concepts. If you are a plete beginner, you might want to explore Visual C Express Edition, which is available on the Web. You can also take advantage of any of several excellent books and Web resources on C to learn practical programming skills.C syntax is highly expressive, yet with less than 90 keywords, it is also simple and easy to learn. The curlybrace syntax of C will be instantly recognizable to anyone familiar with C, C++ or Java. Developers who know any of these languages are typically able to begin working productively in C within a very short time. C syntax simplifies many of the plexities of C++ while providing power