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Thursday, July 28, 2011

ASP.NET Environment

ASP.NET Environment
The Web development environment described in these tutorials is based on ASP.NET technologies. ASP.NET is Microsoft's programming framework that enables the development of Web applications and services. Part of the .NET Platform, it is an easy and scalable way to build, deploy, and run Web applications that can target any browser or Web-aware device. In fact, one of the motivating factors behind the development of the .NET platform is the increasing use of the Internet in communicating among all sorts of devices, from standard desktop browsers through various hand-held, portable, and yet-to-be-invented devices.

ASP.NET is the fastest-growing Web development environment in use today. It powers many of the high-performance commerical Web sites, including Dell Computer, Merrill Lynch, the London Stock Exchange, NASDAQ, JetBlue Airways, USA Today, Home Shopping Network, Weight Watchers, Bank One, and Century 21. In addition, thousands of smaller private companies and public organizations continue to adopt ASP.NET as a powerful and convenient solution to wide-ranging Web processing needs. It is also a personal Web development environment. Many Web hosting services support ASP.NET technologies for personal Web sites. It can even be run on stand-alone desktop or laptop PCs with Windows XP Professional installed.

Programming Environment
ASP.NET has a rich set of software objects to work with in an object-oriented and compiled programming environment. Much of the functionality takes place in the background with details hidden from view of, and usually hidden from concern by, the programmer. All built-in software objects have easy-to-use programming interfaces permitting you to perform elaborate or complex processing with simple and straight-forward code.
Under ASP.NET 2.0 the programming environment takes on the feel of declarative programming rather than conventional logical programming. That is, programs, or scripts, are descriptions of what processing to perform moreso than how to perform it. Traditional programming requires exacting, detailed instructions on the sequence of processing steps a computer performs to generate its output. Under ASP.NET 2.0 these processing steps are largely encapsulated within available software objects. The programming task becomes one of selecting appropriate objects and requesting their properties and methods to return expected results. The details about how this processing takes place is of little concern.

It is for this reason that "programming" become "scripting" under ASP.NET. The programmer works with a higher-level set of instructions to carry out processing. Detailed programming logic is replaced by requests for services. The programmer simply declares what processing is needed; ASP.NET returns the results. The hard work of programming is prepackaged inside the components that are called.

The programming environment supports more than 25 .NET languages, including built-in support for VB.NET, C#, and JScript.NET. In this tutorial all server code is implement in Visual Basic (VB.NET). As a fully object-oriented environment, the .NET Framework offers over 4500 software classes that encapsulate rich functionality like XML, data access, file upload, regular expressions, image generation, performance monitoring and logging, transactions, SMTP mail, and much more. These classes provide an extensive set of objects, properties, and methods accessible through Visual Basic to enhance your Web applications.

All of the processing functionality of VB.NET is built into ASP.NET. The primary difference in the two environments is in how input and output activities are performed. User interaction under ASP.NET is, of course, through a Web browser. Therefore, some of the form controls you may have used under VB.NET do not have ASP.NET equivalents. Still, new Web Form controls in ASP.NET that replace many of the standard HTML tags bring the two environments closer together. As both environments are further developed there is likely to be convergence of the two technologies into one. Applications development for the desktop and for the Web will be virtually indistinguishable.

Though code is compiled, ASP.NET automatically detects any code changes, dynamically compiles the files if needed, and stores the compiled results for reuse in subsequent requests. Dynamic compilation ensures that applications are up to date, and compiled execution makes them fast. There is a short delay when a page is first accessed and compiled. Subsequent accesses, though, retrieve the compiled, cached version of the page for immediate execution.

Instructional Focus and Assumptions

Web development pertains to the use of Web technologies to build client and server processing components, to integrate them as applications within intranet, internet, and extranet processing systems, and to deploy them across the Web to conduct the private and public business affairs of organizations. The skill set to accomplish these tasks range well beyond the ability to save Web pages from a word processing program, to drag and drop a simple Web site with a desktop package, or even to hard-code pages with HTML and a scattering of plug-ins.
In the final analysis, the Web developer needs insight into the operational and management processes of organizations, an understanding of how work flows produce and rely upon information flows in the production of goods and services, an ability to abstract and model these business systems around the hardware and software technologies available, and the technical skills to build Web-based systems that operationalize these models.
It is sometimes too easy to view Web development from a purely technical perspective. The wise developer, however, is a systems analyst, one who understands organizational structures, work-flow processes, and the human dynamics that make them operate. Web-based systems are, first and foremost, business processes. They exist for the purpose of effecting outcomes in the best interests of the enterprise. They do not exist as technical playgrounds for the developer. Web development, then, is a problem analysis and solution development exercise, applied within the broader context of organizational goals and the cultures that pursue them. If you do not understand the purpose and functioning of the enterprise, it is unlikely you can develop systems to support it.
Web development is also an integration exercise. The systems design task is to bring to bear collections of hardware, software, people, and procedures to carry out an activity. Thus, a systems perspective is crucial for tying all the pieces together into something functional, productive, cost-effective, and friendly. A partner skill is programming ability, at least having programming sensibilities if not language skills. At the implementation level Web development is a programming exercise, moderated somewhat as a scripting exercise in current-day practice. You should think like a programmer even if you aren't one.
Finally, Web development is a creative process. So often the work is to devise something new where nothing has existed before. Rather than following directives and well-conceived plans, your imagination might have to create those plans for the artist in you to pursue them. Controlled flights of fancy serve the Web developer well.
The Web developer, then, needs creative imagination, organizational sensibilities, and a broad skill set applied through programming logic to build applications that service the information processing needs of modern organizations. These tutorials can't provide all of that; however, they do cover a basic subset of technical tools and problem-solving skills needed to create dynamic, interactive Web sites.
On the browser side, XHTML and CSS skills are assumed; JavaScript and Dynamic HTML techniques are helpful but not necessary. Visual Basic (VB.NET) is used as the server scripting language. You should have good facility in its use, primarily in coding its decision and control structures and in calling subprograms and functions. Visual Basic is the default server language under ASP.NET, which is the assumed development environment. The tutorials discuss and illustrate ASP.NET 2.0, released early in November, 2005. Also covered are the built-in ASP.NET software objects needed to perform input, processing, output, and storage functions under direction of Visual Basic scripts. On the database side, examples are presented for Microsoft Access, and fundamental use of the SQL language is described. ADO.NET components are used for script interaction with databases.
As you can see, ASP.NET is not an isolated development environment that can be exercised in the absence of other important Web development skills. As best possible, these supporting skills are kept to a minimum in these tutorials in order to concentrate on the task at hand. Nonetheless, a professional Web developer maintains a full repertoire of Web design, layout, styling, browser scripting, server programming, and data access skills. Although you might not have had exposure to all of these technologies, you should be able to follow the instructions and begin creating your own Web-based applications.
 ASP.NET Environment


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