Section 21.9. Wrap-Up

21.9. Wrap-Up

In this chapter, we introduced Web application development using ASP.NET and Visual Web Developer 2005 Express. We began by discussing the simple HTTP transactions that take place when you request and receive a Web page through a Web browser. You then learned about the three tiers (i.e., the client or top tier, the business logic or middle tier and the information or bottom tier) that comprise most Web applications.

Next, we explained the role of ASPX files (i.e., Web Form files) and code-behind files, and the relationship between them. We discussed how ASP.NET compiles and executes Web applications so that they can be displayed as XHTML in a Web browser. You also learned how to build an ASP.NET Web application using Visual Web Developer.

The chapter demonstrated several common ASP.NET Web controls used for displaying text and images on a Web Form. You learned how to use an AdRotator control to display randomly selected images. We also discussed validation controls, which allow you to ensure that user input on a Web page satisfies certain requirements.

We discussed the benefits of maintaining a user's state information across multiple pages of a Web site. We then demonstrated how you can include such functionality in a Web application using either cookies or session tracking with HttpSessionState objects.

Finally, we presented two case studies on building ASP.NET applications that interact with databases. First, we showed how to build a guestbook application that allows users to submit comments about a Web site. You learned how to save the user input in a SQL Server database and how to display past submissions on the Web page.

The second case study presented a secure Web application that requires users to log in before accessing information from the Books database (discussed in Chapter 20). You used the Web Site Administration Tool to configure the application to use forms authentication and prevent anonymous users from accessing the book information. This case study explained how to use the new ASP.NET 2.0 Login, CreateUserWizard, LoginName and LoginStatus controls to simplify user authentication. You also learned to create a uniform look-and-feel for a Web site using a master page and several content pages.

In the next chapter, we continue our coverage of ASP.NET technology with an introduction to Web services, which allow methods on one machine to call methods on other machines via common data formats and protocols, such as XML and HTTP. You will learn how Web services promote software reusability and interoperability across multiple computers on a network such as the Internet.