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About the Author

Cristian Darie and Zak Ruvalcaba

Cristian is a software engineer with experience in a wide range of technologies, and author of numerous technical books. If you want to say "hi," you can reach Cristian through his personal website at http://www.cristiandarie.ro. Zak Ruvalcaba holds a Bachelor's degree from San Diego State University and a Master of Science in Instructional Technology from National University in San Diego.

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ASP.NET 2.0: A Getting Started Guide

ASP.NET is one of the most exciting web development technologies on offer today. When Microsoft released the first version a few years ago, many web developers thought all their dreams had come true. Here was a powerful platform with lots of built-in functionality, astonishing performance levels, and one of the best IDEs (Integrated Development Environments) around: Visual Studio. What more could anyone want? Indeed, ASP.NET showed the way for the faster, easier, and more disciplined development of dynamic web sites, and the results were impressive.

Time has passed, and ASP.NET has grown. ASP.NET 2.0 comes with extraordinary new features as well as an expanded and more powerful underlying framework. Not only that, but the basic versions of all development tools, including Visual Web Developer 2005 Express Edition and SQL Server 2005 Express Edition, are free!

This book--SitePoint's Build Your Own ASP.NET Web Site Using VB and C#, Second Edition--shows you how to use all these technologies together in order to produce fantastic results. It'll take you step by step through each task, showing you how to get the most out of each technology and tool. Developers who have already worked with earlier versions of ASP.NET will find that the latest version has changed so much that entire chapters of this book are devoted to ASP.NET 2.0-specific features.

In this excerpt, which contains the first four chapters of the book, we'll start out by setting up your system for .NET development. In Chapter 2, we'll step through the basics of ASP.NET, and learn about the parts of the page, view state and directives, and the ASP.NET languages. Chapter 3 introduces VB and C# programming basics, from control and page events to namespaces and code-behind files. The final chapter in this excerpt, Chapter 4, pulls together all the practical information we've discussed as we build web forms, and put Web and HTML server controls, web user controls, master pages and Cascading Style Sheets into action!

We're going to cover a lot of ground in the coming pages, so if you like, feel free to download and read these chapters offline.

Let's begin!

What is ASP.NET?

For years, the Active Server Pages (ASP) technology was arguably the leading choice for web developers building dynamic web sites on Windows web servers, as it offered flexible yet powerful scripting capabilities. Early in 2002, Microsoft released a new technology for Internet development called ASP.NET. ASP.NET represents a leap forward from ASP both in its sophistication and the productivity gains it achieves for developers. It continues to offer flexibility in terms of language support, but rather than a range of simple scripting languages, several fully-fledged programming languages are now at the fingertips of ASP.NET developers. Development in ASP.NET requires not only an understanding of HTML and web design, but also a firm grasp of the concepts of object oriented programming and development.

In the next few sections, we'll introduce you to the basics of ASP.NET. We'll walk through the process of installing it on your web server, and step through a simple example that demonstrates how ASP.NET pages are constructed. But first, let's define what ASP.NET actually is.

ASP.NET is a server-side technology for developing web applications based on the Microsoft .NET Framework. Let's break that jargon-filled sentence down.

ASP.NET is a server-side technology; that is, it runs on the web server. Most web designers start their careers learning client-side technologies like HTML, JavaScript, and Cascading Style Sheets (CSS). When a web browser requests a web page created with only client-side technologies, the web server simply grabs the files that the browser (or client) requests and sends them down the line. The client is entirely responsible for reading the markup in those files and interpreting that markup to display the page on the screen.

Server-side technologies, like ASP.NET, are different. Instead of being interpreted by the client, server-side code (for example, the code in an ASP.NET page) is interpreted by the web server. In the case of ASP.NET, the code in the page is read by the server and used to generate HTML, JavaScript, and CSS that is then sent to the browser. Since the processing of the ASP.NET code occurs on the server, it's called a server-side technology. As Figure 1.1 shows, the client only sees the HTML, JavaScript, and CSS. The server is entirely responsible for processing the server-side code.

Figure 1.1. A user interacting with a web application

Note the three roles involved in such a transaction:

• user - Never forget that there's a real person at the end (or beginning) of the line.
• web client - This is the software program that the person uses to interact to the web application. The client is usually a web browser, such as Internet Explorer or Firefox.
• web server - This is the software program located on the server. It processes requests made by the web client.

ASP.NET is a technology for developing web applications. A web application is just a fancy name for a dynamic web site. Web applications usually (but not always) store information in a database, and allow visitors to the site to access and change that information. Many different programming technologies and supported languages have been developed to create web applications; PHP, JSP, Ruby on Rails, CGI, and ColdFusion are just a few of the more popular ones. However, rather than tying you to a specific technology and language, ASP.NET lets you write web applications using a variety of familiar programming languages.

ASP.NET uses the Microsoft .NET Framework. The .NET Framework collects all the technologies needed for building Windows desktop applications, web applications, web services, and so on, into a single package, and makes them available to more than 40 programming languages.

Even with all the jargon explained, you're probably still wondering what makes ASP.NET so good. The truth is that there are many server-side technologies around, each of which has its own strengths and weaknesses. Yet ASP.NET has a few features that really are unique:

• ASP.NET lets you use your favorite programming language, or at least one that's close to it. The .NET Framework currently supports over 40 languages, and many of these may be used to build ASP.NET web sites. The most popular choices are C# (pronounced "C sharp") and Visual Basic (or VB), which are the ones we'll cover in this book.
• ASP.NET pages are compiled, not interpreted. In ASP.NET's predecessor, ASP, pages were interpreted: every time a user requested a page, the server would read the page's code into memory, figure out how to execute the code (that is, interpret the code), and execute it. In ASP.NET, the server need only figure out how to execute the code once. The code is compiled into efficient binary files, which can be run very quickly, again and again, without the overhead involved in re-reading the page each time. This represents a big jump in performance from the old days of ASP.
• ASP.NET has full access to the functionality of the .NET Framework. Support for XML, web services, database interaction, email, regular expressions, and many other technologies are built right into .NET, which saves you from having to reinvent the wheel.
• ASP.NET allows you to separate the server-side code in your pages from the HTML layout. When you're working with a team composed of programmers and design specialists, this separation is a great help, as it lets programmers modify the server-side code without stepping on the designers' carefully crafted HTML?and vice versa.
• ASP.NET makes it easy to reuse common User Interface elements in many web forms, as it allows us to save those components as independent web user controls. During the course of this book, you'll learn how to add powerful features to your web site, and to reuse them in many places with a minimum of effort.
• You can get excellent tools that assist in developing ASP.NET web applications. Visual Web Developer 2005 is a free, powerful visual editor that includes features such as code autocompletion, code formatting, database integration functionality, a visual HTML editor, debugging, and more. In the course of this book, you'll learn how to use this tool to build the examples we discuss.
• The .NET Framework was first available only to the Windows platform, but thanks to projects such as Mono, it's since been ported to other operating systems.

Still with me? Great! It's time to gather our tools and start building!

Installing the Required Software

If you're going to learn ASP.NET, you first need to make sure you have all the necessary software components installed and working on your system. Let's take care of this before we move on.

• Internet Information Services (IIS) or Cassini - IIS is the web server of choice for running ASP.NET web applications. You'll need your copy of the Windows CD to install and configure it. Unfortunately, some versions of Windows (such as Windows XP Home Edition) don't support IIS. If you're one of those users, there's Cassini. Cassini is a small web server designed for hobbyists who are looking to build ASP.NET web sites. It isn't as robust, powerful, or user-friendly as IIS, but it will be sufficient for our purposes. When we come to use Visual Web Developer in Chapter 5, Building Web Applications, we'll be making use of that product's built-in development web server, so not having access to IIS on your system won't be a problem.
• a modern web browser - Throughout this book, we'll be using Internet Explorer 6, but you can use other browsers during development if you wish. Any modern browser will do.
• .NET Framework 2.0 - As we've already discussed, the .NET Framework drives ASP.NET. When you install the .NET Framework, you'll automatically install the files necessary to run ASP.NET. You're likely to have the .NET Framework already, as it installs automatically through the Windows Update service.
• .NET Framework Software Development Kit (SDK) - The .NET Framework 2.0 Software Development Kit (SDK) is a free download that contains the necessary Web Application development tools, a debugger for error correcting, and a suite of samples and documentation.

We're also going to need a database. In this book, we'll use the following:

• Microsoft SQL Server 2005 Express Edition - This is the free, but still fully functional, version of SQL Server 2005. If you worked with previous versions of these technologies, you should know that SQL Server 2005 Express is a replacement for the previous Microsoft SQL Data Engine (MSDE). You can read more on the differences between various SQL Server 2005 editions at the Microsoft site.
• SQL Server Management Studio Express - Because the Express Edition of SQL Server doesn't ship with any visual management tools, you can use this free tool, also developed by Microsoft, to access your SQL Server 2005 databases.