ASP.NET Features

ASP.NET includes many new advances in web development technology. Here are just a few of the more famous ones.

• Compiled code. All of the code you write for ASP.NET applications is fully compiled into standard .NET DLL assemblies. When the client makes a request for a file with an .aspx extension, Internet Information Server locates this file (which contains HTML or combined HTML/ASP.NET content) and the associated compiled DLL, and uses them together to process the page content. You can pre-compile the DLL before deployment, or you can let ASP.NET compile it on the fly the first time the .aspx file gets called.

• .NET support. ASP.NET applications can access the full .NET Framework Class Libraries (except those that specifically target desktop development). Any of the cool features and classes you have in desktop .NET applications are right there in web applications as well.

• Object-based. HTML tags, such as the <textarea> tag, are really just text strings within a larger HTML text file. Pre-.NET server-side scripting was an exercise in string concatenation, building up a larger file from smaller content strings. ASP.NET treats all web-page elements as true objects, complete with properties and events. And some of these objects implement complex client-side controls, backed up by hundreds of lines of client-side script that you get for free.

• Deployment simplicity. Managing server-side scripts and custom DLLs before .NET was not very fun. Certain types of changes required a full shutdown of Internet Information Server, or at least of the portion that controlled the application being changed. ASP.NET lets you make changes on a production system without impacting active users. If you replace a compiled DLL, ASP.NET will start using it immediately, but still keep the older version around until all existing clients have detached from it.

• Browser independence. The web-page objects that you use in ASP.NET take responsibility for generating their own HTML and client-side script content. Many of them take the client's browser type and version into account, enhancing or reducing features automatically when needed. As an ASP.NET developer, you don't even have to know which browser is being used.

• Extensibility. If you want to enhance a web-page element, you can derive from its class and add the new enhanced features, just as you do with any other .NET class.

Of course, there are more great features than the few I listed here. But you're probably ready to see ASP.NET in action. Let's get started.