Chapter 6. Configuring Application Domains

In Chapter 5, I describe application domains as a construct used to isolate groups of assemblies that are loaded into the same process. An important aspect of this isolation is the ability for the creator of an application domain to be able to constrain various aspects of how the domain operates. For example, a domain's creator must be able to limit the locations from which unsigned assemblies can be loaded into the domain. Other examples include the ability to control how version policy applies to assemblies in the domain and to specify the configuration file where application-specific settings can be stored. These aspects of application domain behavior, along with many others, can be customized through various settings specified when the domain is created. In this chapter, I describe how you can use these settings to customize the behavior of application domains to fit your particular scenario.

Application domain managers also play a key role in your ability to customize how application domains are created in the process. Recall from the previous chapter that an instance of your application domain manager is created by the CLR in every application domain. As part of this process, the CLR calls your application domain manager both before and after a new domain has been created to give you a chance to configure it. This detail is important because it gives you, the author of an extensible application, the ability to decide how all domains are created in the process, including those created by any add-ins you have loaded, not just the ones you create yourself. After I describe the full set of application domain configuration settings, I explain your domain manager's role in customizing how application domains are created in a process.