Introduction

ASP.NET applications have not changed a great deal through ASP s development. Granted, the actual inner workings have definitely changed dramatically, but the application concept itself has not; an ASP.NET application is still defined as the developer-created files and directories that can be requested, invoked, and processed through ASP.NET within its local directory structures.

Each application can have within its own local subdirectory a file named Global.asax that defines application parameters to Internet Information Server (IIS), and to the ASP.NET Web application scripts local to it. Global.asax tells IIS what to do when the application is started and how to handle processing, depending on the state of the application.

An application can have both an application state and a session state. They are both very useful and versatile facilities when used knowledgably, reflecting the functionality that .NET has provided them. Each of these states can be further customized to contain the information needed to refine the application to your purposes.

In this chapter we will look at how you can implement application and session functionality, and will work through examples of using state in ASP.NET projects.

Understanding ASP.NET Applications

As previously outlined, ASP.NET applications collect Web site resources into manageable organizational units within the Web server s file system hierarchy. But what exactly does this mean to the programmer?

A user expects a Web site to simply serve up the pages the visitor has asked for. He or she may be pleasantly surprised that the Web site knows who they are...