How to: Unload an Application Domain

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When you have finished using an application domain, unload it using the System.AppDomain.Unload

method. The Unload method gracefully shuts down the specified application domain. During the

unloading process, no new threads can access the application domain, and all application domain–

specific data structures are freed.

Assemblies loaded into the application domain are removed and are no longer available. If an assembly

in the application domain is domain-neutral, data for the assembly remains in memory until the entire

process is shut down. There is no mechanism to unload a domain-neutral assembly other than shutting

down the entire process. There are situations where the request to unload an application domain does

not work and results in a CannotUnloadAppDomainException.

The following example creates a new application domain called MyDomain, prints some information

to the console, and then unloads the application domain. Note that the code then attempts to print the

friendly name of the unloaded application domain to the console. This action generates an exception

that is handled by the try/catch statements at the end of the program.

Example

Visual Basic

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Imports System

Imports System.Reflection

Class AppDomain2

Public Shared Sub Main()

Console.WriteLine("Creating new AppDomain.")

Dim domain As AppDomain = AppDomain.CreateDomain("MyDomain", Nothing)

Console.WriteLine(("Host domain: " + AppDomain.CurrentDomain.FriendlyName))

Console.WriteLine(("child domain: " + domain.FriendlyName))

AppDomain.Unload(domain)

Try

Console.WriteLine()

Console.WriteLine(("Host domain: " + AppDomain.CurrentDomain.FriendlyName))

' The following statement creates an exception because the domain no longer exists.

Console.WriteLine(("child domain: " + domain.FriendlyName))

Catch e As AppDomainUnloadedException

Console.WriteLine("The appdomain MyDomain does not exist.")

End Try

End Sub 'Main

End Class 'AppDomain2

C#

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using System;

using System.Reflection;

class AppDomain2

{

public static void Main()

{

Console.WriteLine("Creating new AppDomain.");

AppDomain domain = AppDomain.CreateDomain("MyDomain", null);

Console.WriteLine("Host domain: " + AppDomain.CurrentDomain.FriendlyName);

Console.WriteLine("child domain: " + domain.FriendlyName);

AppDomain.Unload(domain);

try

{

Console.WriteLine();

Console.WriteLine("Host domain: " + AppDomain.CurrentDomain.FriendlyName);

// The following statement creates an exception because the domain no longer exists.

Console.WriteLine("child domain: " + domain.FriendlyName);

}

catch (AppDomainUnloadedException e)

{

Console.WriteLine("The appdomain MyDomain does not exist.");

}

}

}