Book VI in C#

Generation ANSI/AIM Code 39 in C# Book VI

1: Looking at How ASPNET Works with C# 629 2: Building Web Applications 641 3: Controlling Your Development Experience 659 4: Leveraging the NET Framework 685 5: Digging into Web Construction 703

1: Looking at How ASPNET Works with C#

hen I first started writing about World Wide Web applications, I had to describe the Web first There were still a significant number of programmers who didn t know what it was, or thought it was CompuServe I don t really have that problem anymore The World Wide Web is now ubiquitous Programmers of all stripes use the Web for research and communication Providers use it for product updates and documentation It is everywhere All the more reason to know how to code in the Web environment Problem is that there are so many so-called frameworks for development that it is nearly impossible to decide which to use with a reasonable methodology You almost have the draw straws If you are working in a Microsoft environment, and if you are writing a nonexceptional program, I recommend that you use plain, vanilla ASPNET Why Sempf s Fourth Law: Simplicity above all ASPNET is a straightforward platform for Web creation ASPNET has its share of problems, most of which involve writing Google (or some other really big complicated program) You probably aren t writing Google, so don t worry about it If your site gets famous, you can get some venture capital and rewrite it into some custom framework For now, just get your site written That s what ASPNET enables you to do get the job done With ASPNET, you can write a good Web site quickly, one that can be hosted just about anywhere No one can ask for much more than that This chapter delves into the details of using ASPNET with C#

A Web application is a computer program that uses a very light client interface communicating with a server over the Internet in a stateless manner Stateless means that the computer browsing the site and the server providing the site don t maintain a connection You can see this process at a high level in Figure 1-1

5 generated page to the User User Submits Shopping Cart Order on Web Site STOP Web Application Server Database Servers

Data exchanged between User and Web Server via port 80/443 Data exchanged between Web Server, Web Application Server, Database Server and Database Two-Way traf c between User and Web Server

The client requests a document from the server, and the server sends the document when it gets around to it The document, usually a combination of Hypertext Markup Language (HTML), Cascading Style Sheets (CSS), and JavaScript, contains standardized elements which make up the interface of the application Why do we need this If there is just a set of documents on the server and the client is just requesting one after another, what s the point of that Of course, getting a document is a good thing, but where does the application part come in

The answer is within Web applications Web applications are powerful because the server can construct the document on the fly whenever it receives a request This server process is what makes Web applications work (See Figure 1-2) Don t get me wrong, the light client interface called the Web browser or just the browser provides some important functionality It handles the user interface and can do things independently of the server The server is largely where it s at, though Because the server can remember things from moment to moment, and because it is assumed that the client forgets everything from page to page, the server is where the long-running communications all reside