ASP .NET is perhaps the flagship of the .NET development product range. Microsoft has thrown away the old ASP model of developing Web applications using a combination of script and COM components . ASP .NET replaces the old model with a new "code-behind" model that combines fully compiled business logic running on the server with built-in or custom graphical controls running in the client Web browser. Another major feature of ASP .NET is XCOPY deployment of applications in many scenarios, which is a huge improvement over the ASP deployment story.
The new development model offered by ASP .NET very much resembles (perhaps deliberately) the Windows Forms event-driven model of coding. ASP.Classic developers are facing a bigger paradigm shift than their VB colleagues because of this shift from procedural code to event-driven code, and the resulting separation of presentation code from business code. Their VB.Classic colleagues don't escape completely unscathed, however, as the ASP .NET similarity to the Windows Forms event-driven development model tends to hide differences that can cause bugs for the unwary.
This chapter investigates the debugging of ASP .NET applications, with the exception of XML Web services because these are discussed in Chapter 8. You'll focus on the debugging of ASP .NET programs running under Internet Information Server (IIS) 5. x and 6.0, and you'll also investigate ASP .NET tracing and error handling.