Programming with Application Domains

Application domains are usually created and manipulated programmatically by runtime hosts. However, sometimes an application program might also want to work with application domains. For example, an application program could load an application component into a domain to be able to unload the domain (and the component) without having to stop the entire application.

The AppDomain class is the programmatic interface to application domains. This class includes methods to create and unload domains, to create instances of types in domains, and to register for various notifications such as application domain unloading. The following table lists commonly used AppDomain methods.

AppDomain Method



Creates a new application domain. It is recommended that you use an overload of this method that specifies an AppDomainSetup object. This is the preferred way to set the properties of a new domain, such as the application base, or root directory for the application; the location of the configuration file for the domain; and the search path that the common language runtime is to use to load assemblies into the domain.

ExecuteAssembly and ExecuteAssemblyByName

Executes an assembly in the application domain. This is an instance method, so it can be used to execute code in another application domain to which you have a reference.


Creates an instance of a specified type in the application domain, and returns a proxy. Use this method to avoid loading the assembly containing the created type into the calling assembly.


Performs a graceful shutdown of the domain. The application domain is not unloaded until all threads running in the domain have either stopped or are no longer in the domain.


The common language runtime does not support serialization of global methods, so delegates cannot be used to execute global methods in other application domains.

The unmanaged interfaces described in the common language runtime Hosting Interfaces Specification also provide access to application domains. Runtime hosts can use interfaces from unmanaged code to create and gain access to the application domains within a process.

See Also



AppDomain methods

Other Resources

Application Domains