AppDomainUnloadedException Classe

Definição

public ref class AppDomainUnloadedException : SystemException

[System.Serializable]
public class AppDomainUnloadedException : SystemException

[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public class AppDomainUnloadedException : SystemException

public class AppDomainUnloadedException : SystemException

[<System.Serializable>]
type AppDomainUnloadedException = class
    inherit SystemException

[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type AppDomainUnloadedException = class
    inherit SystemException

type AppDomainUnloadedException = class
    inherit SystemException

Public Class AppDomainUnloadedException
Inherits SystemException

Herança

Object

Exception

SystemException

AppDomainUnloadedException

Atributos

SerializableAttribute ComVisibleAttribute

Exemplos

Esta seção contém dois exemplos de código. O primeiro exemplo demonstra os efeitos de um AppDomainUnloadedException em vários threads e o segundo mostra o descarregamento de domínio de aplicativo elementar.

Exemplo 1

O exemplo de código a seguir define uma classe TestClass que pode ser marshalada entre limites de domínio do aplicativo e uma classe Example que contém um método static (Shared no Visual Basic) ThreadProc. O ThreadProc método cria um domínio de aplicativo, cria um TestClass objeto no domínio e chama um método do TestClass qual descarrega o domínio em execução, causando um AppDomainUnloadedException.

O TestClass método é executado sem tratamento de exceção de um ThreadPool thread e de um thread comum, demonstrando que a exceção sem tratamento encerra a tarefa ou o thread, mas não o aplicativo. Em seguida, ele é executado com e sem tratamento de exceção do thread principal do aplicativo, demonstrando que ele encerra o aplicativo se não for tratado.

using System;
using System.Threading;
using System.Runtime.InteropServices;

public class Example
{
    public static void Main()
    {
        // 1. Queue ThreadProc as a task for a ThreadPool thread.
        ThreadPool.QueueUserWorkItem(ThreadProc, " from a ThreadPool thread");
        Thread.Sleep(1000);

        // 2. Execute ThreadProc on an ordinary thread.
        Thread t = new Thread(ThreadProc);
        t.Start(" from an ordinary thread");
        t.Join();

        // 3. Execute ThreadProc on the main thread, with
        //    exception handling.
        try
        {
            ThreadProc(" from the main application thread (handled)");
        }
        catch (AppDomainUnloadedException adue)
        {
            Console.WriteLine("Main thread caught AppDomainUnloadedException: {0}", adue.Message);
        }

        // 4. Execute ThreadProc on the main thread without
        //    exception handling.
        ThreadProc(" from the main application thread (unhandled)");

        Console.WriteLine("Main: This message is never displayed.");
    }

    private static void ThreadProc(object state)
    {
        // Create an application domain, and create an instance
        // of TestClass in the application domain. The first
        // parameter of CreateInstanceAndUnwrap is the name of
        // this executable. If you compile the example code using
        // any name other than "Sample.exe", you must change the
        // parameter appropriately.
        AppDomain ad = AppDomain.CreateDomain("TestDomain");
        TestClass tc = (TestClass)ad.CreateInstanceAndUnwrap("Sample", "TestClass");

        // In the new application domain, execute a method that
        // unloads the AppDomain. The unhandled exception this
        // causes ends the current thread.
        tc.UnloadCurrentDomain(state);

        Console.WriteLine("ThreadProc: This message is never displayed.");
    }
}

// TestClass derives from MarshalByRefObject, so it can be marshaled
// across application domain boundaries.
//
public class TestClass : MarshalByRefObject
{
    public void UnloadCurrentDomain(object state)
    {
        Console.WriteLine("\nUnloading the current AppDomain{0}.", state);

        // Unload the current application domain. This causes
        // an AppDomainUnloadedException to be thrown.
        //
        AppDomain.Unload(AppDomain.CurrentDomain);
    }
}

/* This code example produces output similar to the following:
Unloading the current AppDomain from a ThreadPool thread.

Unloading the current AppDomain from an ordinary thread.

Unloading the current AppDomain from the main application thread (handled).
Main thread caught AppDomainUnloadedException: The application domain in which the thread was running has been unloaded.

Unloading the current AppDomain from the main application thread (unhandled).

Unhandled Exception: System.AppDomainUnloadedException: The application domain in which the thread was running has been unloaded.
   at TestClass.UnloadCurrentDomain(Object state)
   at Example.ThreadProc(Object state)
   at Example.Main()
 */

open System
open System.Threading

// TestClass derives from MarshalByRefObject, so it can be marshaled
// across application domain boundaries.
type TestClass() =
    inherit MarshalByRefObject()
    member _.UnloadCurrentDomain (state: obj) =
        printfn $"\nUnloading the current AppDomain{state}."

        // Unload the current application domain. This causes
        // an AppDomainUnloadedException to be thrown.
        //
        AppDomain.Unload AppDomain.CurrentDomain

let threadProc (state: obj) =
    // Create an application domain, and create an instance
    // of TestClass in the application domain. The first
    // parameter of CreateInstanceAndUnwrap is the name of
    // this executable. If you compile the example code using
    // any name other than "Sample.exe", you must change the
    // parameter appropriately.
    let ad = AppDomain.CreateDomain "TestDomain"
    let tc = ad.CreateInstanceAndUnwrap("Sample", "TestClass") :?> TestClass

    // In the new application domain, execute a method that
    // unloads the AppDomain. The unhandled exception this
    // causes ends the current thread.
    tc.UnloadCurrentDomain state

    printfn "ThreadProc: This message is never displayed."

// 1. Queue ThreadProc as a task for a ThreadPool thread.
ThreadPool.QueueUserWorkItem(threadProc, " from a ThreadPool thread") |> ignore
Thread.Sleep 1000

// 2. Execute ThreadProc on an ordinary thread.
let t = Thread(ParameterizedThreadStart threadProc) 
t.Start " from an ordinary thread"
t.Join()

// 3. Execute ThreadProc on the main thread, with
//    exception handling.
try
    threadProc " from the main application thread (handled)"
with :? AppDomainUnloadedException as adue ->
    printfn $"Main thread caught AppDomainUnloadedException: {adue.Message}"

// 4. Execute ThreadProc on the main thread without
//    exception handling.
threadProc " from the main application thread (unhandled)"

printfn "Main: This message is never displayed."

(* This code example produces output similar to the following:
Unloading the current AppDomain from a ThreadPool thread.

Unloading the current AppDomain from an ordinary thread.

Unloading the current AppDomain from the main application thread (handled).
Main thread caught AppDomainUnloadedException: The application domain in which the thread was running has been unloaded.

Unloading the current AppDomain from the main application thread (unhandled).

Unhandled Exception: System.AppDomainUnloadedException: The application domain in which the thread was running has been unloaded.
   at TestClass.UnloadCurrentDomain(Object state)
   at Example.ThreadProc(Object state)
   at Example.main()
 *)

Imports System.Threading
Imports System.Runtime.InteropServices

Public Class Example
    
    Public Shared Sub Main() 

        ' 1. Queue ThreadProc as a task for a ThreadPool thread.
        ThreadPool.QueueUserWorkItem(AddressOf ThreadProc, _
            " from a ThreadPool thread")
        Thread.Sleep(1000)
        
        ' 2. Execute ThreadProc on an ordinary thread.
        Dim t As New Thread(AddressOf ThreadProc)
        t.Start(" from an ordinary thread")
        t.Join()
        
        ' 3. Execute ThreadProc on the main thread, with 
        '    exception handling.
        Try
            ThreadProc(" from the main application thread (handled)")
        Catch adue As AppDomainUnloadedException
            Console.WriteLine("Main thread caught AppDomainUnloadedException: {0}", _
                adue.Message)
        End Try
        
        ' 4. Execute ThreadProc on the main thread without
        '    exception handling.
        ThreadProc(" from the main application thread (unhandled)")
        
        Console.WriteLine("Main: This message is never displayed.")
    
    End Sub 
    
    Private Shared Sub ThreadProc(ByVal state As Object) 
        ' Create an application domain, and create an instance
        ' of TestClass in the application domain. The first
        ' parameter of CreateInstanceAndUnwrap is the name of
        ' this executable. If you compile the example code using
        ' any name other than "Sample.exe", you must change the
        ' parameter appropriately.
        Dim ad As AppDomain = AppDomain.CreateDomain("TestDomain")
        Dim o As Object = ad.CreateInstanceAndUnwrap("Sample", "TestClass")
        Dim tc As TestClass = CType(o, TestClass)
        
        ' In the new application domain, execute a method that
        ' unloads the AppDomain. The unhandled exception this
        ' causes ends the current thread.
        tc.UnloadCurrentDomain(state)
        
        Console.WriteLine("ThreadProc: This message is never displayed.")
    
    End Sub
End Class 

' TestClass derives from MarshalByRefObject, so it can be marshaled
' across application domain boundaries. 
'
Public Class TestClass
    Inherits MarshalByRefObject
    
    Public Sub UnloadCurrentDomain(ByVal state As Object) 
        Console.WriteLine(vbLf & "Unloading the current AppDomain{0}.", state)
        
        ' Unload the current application domain. This causes
        ' an AppDomainUnloadedException to be thrown.
        '
        AppDomain.Unload(AppDomain.CurrentDomain)
    
    End Sub 
End Class 

' This code example produces output similar to the following:
'
'Unloading the current AppDomain from a ThreadPool thread.
'
'Unloading the current AppDomain from an ordinary thread.
'
'Unloading the current AppDomain from the main application thread (handled).
'Main thread caught AppDomainUnloadedException: The application domain in which the thread was running has been unloaded.
'
'Unloading the current AppDomain from the main application thread (unhandled).
'
'Unhandled Exception: System.AppDomainUnloadedException: The application domain in which the thread was running has been unloaded.
'   at TestClass.UnloadCurrentDomain(Object state)
'   at Example.ThreadProc(Object state)
'   at Example.Main()
'

Exemplo 2

O exemplo de código a seguir cria e descarrega um domínio de aplicativo e demonstra que um AppDomainUnloadedException é gerado em uma tentativa subsequente de acessar o domínio descarregado.

using namespace System;
using namespace System::Reflection;
using namespace System::Security::Policy;

//for evidence Object*
int main()
{
   
   //Create evidence for the new appdomain.
   Evidence^ adevidence = AppDomain::CurrentDomain->Evidence;
   
   // Create the new application domain.
   AppDomain^ domain = AppDomain::CreateDomain( "MyDomain", adevidence );
   Console::WriteLine( "Host domain: {0}", AppDomain::CurrentDomain->FriendlyName );
   Console::WriteLine( "child domain: {0}", domain->FriendlyName );
   
   // Unload the application domain.
   AppDomain::Unload( domain );
   try
   {
      Console::WriteLine();
      
      // Note that the following statement creates an exception because the domain no longer exists.
      Console::WriteLine( "child domain: {0}", domain->FriendlyName );
   }
   catch ( AppDomainUnloadedException^ /*e*/ ) 
   {
      Console::WriteLine( "The appdomain MyDomain does not exist." );
   }

}

using System;
using System.Reflection;
using System.Security.Policy;
class ADUnload
{
    public static void Main()
    {

        //Create evidence for the new appdomain.
        Evidence adevidence = AppDomain.CurrentDomain.Evidence;

        // Create the new application domain.
        AppDomain domain = AppDomain.CreateDomain("MyDomain", adevidence);

                Console.WriteLine("Host domain: " + AppDomain.CurrentDomain.FriendlyName);
                Console.WriteLine("child domain: " + domain.FriendlyName);
        // Unload the application domain.
        AppDomain.Unload(domain);

        try
        {
        Console.WriteLine();
        // Note that 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.");
        }
    }
}

open System

//Create evidence for the new appdomain.
let adevidence = AppDomain.CurrentDomain.Evidence

// Create the new application domain.
let domain = AppDomain.CreateDomain("MyDomain", adevidence)

printfn $"Host domain: {AppDomain.CurrentDomain.FriendlyName}"
printfn $"child domain: {domain.FriendlyName}"
// Unload the application domain.
AppDomain.Unload domain

try
    printfn ""
    // Note that the following statement creates an exception because the domain no longer exists.
    printfn $"child domain: {domain.FriendlyName}"

with :? AppDomainUnloadedException ->
    printfn "The appdomain MyDomain does not exist."

Imports System.Reflection
Imports System.Security.Policy

Class ADUnload
   
   Public Shared Sub Main()

      'Create evidence for the new appdomain.
      Dim adevidence As Evidence = AppDomain.CurrentDomain.Evidence

      ' Create the new application domain.
      Dim domain As AppDomain = AppDomain.CreateDomain("MyDomain", adevidence)
      
      Console.WriteLine(("Host domain: " + AppDomain.CurrentDomain.FriendlyName))
      Console.WriteLine(("child domain: " + domain.FriendlyName))
      ' Unload the application domain.
      AppDomain.Unload(domain)
      
      Try
         Console.WriteLine()
         ' Note that 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
End Class

Comentários

No .NET Framework versão 2.0, um AppDomainUnloadedException que não é tratado no código do usuário tem o seguinte efeito:

• Se um thread tiver sido iniciado no código gerenciado, ele será encerrado. A exceção sem tratamento não tem permissão para encerrar o aplicativo.

• Se uma tarefa estiver sendo executada em um ThreadPool thread, ela será encerrada e o thread será retornado para o pool de threads. A exceção sem tratamento não tem permissão para encerrar o aplicativo.

• Se um thread iniciado em código não gerenciado, como o thread do aplicativo principal, ele será encerrado. A exceção sem tratamento tem permissão para continuar e o sistema operacional encerra o aplicativo.

AppDomainUnloadedException usa o COR_E_APPDOMAINUNLOADED HRESULT, que tem o valor 0x80131014.

Para obter uma lista de valores de propriedade iniciais de uma instância de AppDomainUnloadedException, consulte os construtores de AppDomainUnloadedException.

Confira também

• AppDomain
• Exception
• Tratando e gerando exceções no .NET