Chapter 8. Building Interactive Web Forms

8. Building Interactive Web Forms

Traditionally, building web pages and Web applications has been unlike most other development scenarios. When you build an application in a language like Visual Basic, Pascal, C++, or any of the myriad other languages available, you are expected to know only two things: how to create the interface and how to write code. However, in the Web development arena, you have to master three topics: creating the interface (what the controls look like and do), understanding the underlying working of the environment (the HTML), and writing code. This is almost analogous to having to understand the microprocessor instructions when working in other high-level languages. Even the current leading-edge development tools like Visual Studio 2005 still offer three views of a Web pageDesign view, Source view, and the server-side code itself.

In fact, Web developers have had a tough time over the years. It was fine to expect everyone to learn HTML and write their pages in a text editor in the early days, when the requirements for the pages were much simpler than they are today. In the intervening years, dynamic techniques for creating Web pages blossomed, yet all of them involved a low-level knowledge of the underlying instruction setthe HTML elements and their attributes.

Now, however, the level of complexity for even the most basic Web sites means that developers must be able to escape from the text editor approach and build pages from the same perspective, and using the same approaches, as when building traditional executable and Windows Forms applications.

In this chapter, we look at ASP.NET, and the controls and features it provides, from the point of view of an application developer rather than just a Web developer. You will see howat lastthe approach to building Web applications has moved away from the text editor and HTML guru to the use of a comprehensive development environment with a set of integrated and easy-to-understand controls. Of course, this approach is ideally suited to Web programming newcomers who may not have used earlier environments such as ASP 3.0, PHP, or even plain old HTML. The topics you will see in this chapter are:

• Understanding the control set for ASP.NET and choosing the right control

• Using the rich compound controls provided with ASP.NET

• Implementing validation in your pages

• Building Wizards with the Wizard control

To start with, you will explore the various types of controls that are available in ASP.NET 2.0 and how they relate to the postback architecture and event-driven environment of ASP.NET.