Even with all the software architecture methodologies and development practices available these days, software is still very much a craft. Software libraries such as ASP.NET and Windows Forms go a long way towards making development more standardized and predictable (good things in software practice). However, there are still almost inevitable periods when you need to figure out what's wrong with an application that decides to behave differently than you expected it to.

This chapter covers the support provided by ASP.NET for figuring out what's wrong with your ASP.NET application. As you can imagine, debuging Web applications introduces a whole new set of challenges. Remember, HTTP is basically connectionless, and the only thing the client really gets to see is a snapshot of the application. This chapter shows you how to watch your application as it runs and trace the state of any particular request. We'll also cover managing error pages and trapping application exceptions within ASP.NET.