How to: Unload an Application Domain

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

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(e.GetType().FullName)
            Console.WriteLine("The appdomain MyDomain does not exist.")
        End Try
    End Sub
End Class

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(e.GetType().FullName);
            Console.WriteLine("The appdomain MyDomain does not exist.");
        }
    }
}

using namespace System;
using namespace System::Reflection;

ref class AppDomain2
{
public:
    static void Main()
    {
        Console::WriteLine("Creating new AppDomain.");
        AppDomain^ ___domain = AppDomain::CreateDomain("MyDomain", nullptr);

        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(e->GetType()->FullName);
            Console::WriteLine("The appdomain MyDomain does not exist.");
        }
    }
};

int main()
{
    AppDomain2::Main();
}

See Also

Tasks

How to: Create an Application Domain

Concepts

Programming with Application Domains

Other Resources

Using Application Domains