ASP.NET in a Nutshell

Chapter 20. web.config Reference

ASP.NET provides a completely new model for configuring web applications. This greatly simplified process makes it considerably easier to deploy application configuration settings, the application’s content, and its components. Central to this new configuration model is web.config, an XML-based file that contains the configuration settings for your application. Because the file is written in XML, it is both human- and machine-readable.

web.config files configure applications hierarchically -- i.e., an application can contain more than one web.config file, with each file residing in a separate folder of the application. Settings in a web.config file in a child folder of the application root override the settings of the web.config file in the parent folder. Settings not defined in the child web.config file inherit the settings from the parent web.config file. Figure 20-1 demonstrates these rules of precedence.

Figure 20-1. Inheriting and overriding web.config settings

In addition to inheriting settings from a web.config file defined in a parent folder, all applications on a given machine inherit settings from a file called machine.config. The machine.config file contains default ASP.NET configuration settings, as well as settings for other .NET application types. Thus, in Figure 20-1, the Chapter20 folder inherits the machine.config setting for the ...