AppDomainUnloadedException Klass

Definition

public ref class AppDomainUnloadedException : SystemException

public class AppDomainUnloadedException : SystemException

[System.Serializable]
public class AppDomainUnloadedException : SystemException

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

type AppDomainUnloadedException = class
    inherit SystemException

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

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

Public Class AppDomainUnloadedException
Inherits SystemException

Arv

Object

Exception

SystemException

AppDomainUnloadedException

Attribut

SerializableAttribute ComVisibleAttribute

Exempel

Det här avsnittet innehåller två kodexempel. Det första exemplet visar effekterna av en AppDomainUnloadedException på olika trådar, och det andra visar elementär programdomänens avlastning.

Exempel 1

I följande kodexempel definieras en TestClass-klass som kan konverteras över programdomängränser och en klass Example som innehåller en static (Shared i Visual Basic) ThreadProc metod. Metoden ThreadProc skapar en programdomän, skapar ett TestClass objekt i domänen och anropar en metod TestClass som tar bort den körbara domänen, vilket orsakar en AppDomainUnloadedException.

Metoden TestClass körs utan undantagshantering från en ThreadPool tråd och från en vanlig tråd, vilket visar att det ohanterade undantaget avslutar uppgiften eller tråden men inte programmet. Den körs sedan med och utan undantagshantering från huvudprogramtråden, vilket visar att programmet avslutas om det inte hanteras.

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()
'

Exempel 2

Följande kodexempel skapar och tar bort en programdomän och visar att en AppDomainUnloadedException genereras vid ett efterföljande försök att komma åt den borttagna domänen.

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

Kommentarer

I .NET Framework version 2.0 har en AppDomainUnloadedException som inte hanteras i användarkoden följande effekt:

• Om en tråd startades i hanterad kod avslutas den. Det ohanterade undantaget tillåts inte att avsluta programmet.

• Om en uppgift körs på en ThreadPool tråd avslutas den och tråden returneras till trådpoolen. Det ohanterade undantaget tillåts inte att avsluta programmet.

• Om en tråd startade i ohanterad kod, till exempel huvudprogramtråden, avslutas den. Det ohanterade undantaget tillåts fortsätta och operativsystemet avslutar programmet.

AppDomainUnloadedException använder HRESULT-COR_E_APPDOMAINUNLOADED, som har värdet 0x80131014.

För en lista över inledande egenskapsvärden för en instans av AppDomainUnloadedException, se i AppDomainUnloadedException-konstruktorn.

Se även

• AppDomain
• Exception
• Hantera och utlösa undantag i .NET