AppDomainUnloadedException 类
在尝试访问已卸载的应用程序域时引发的异常。
**命名空间:**System
**程序集:**mscorlib（在 mscorlib.dll 中）
语法
声明
<SerializableAttribute> _
<ComVisibleAttribute(True)> _
Public Class AppDomainUnloadedException
Inherits SystemException
用法
Dim instance As AppDomainUnloadedException
[SerializableAttribute]
[ComVisibleAttribute(true)]
public class AppDomainUnloadedException : SystemException
[SerializableAttribute]
[ComVisibleAttribute(true)]
public ref class AppDomainUnloadedException : public SystemException
/** @attribute SerializableAttribute() */
/** @attribute ComVisibleAttribute(true) */
public class AppDomainUnloadedException extends SystemException
SerializableAttribute
ComVisibleAttribute(true)
public class AppDomainUnloadedException extends SystemException
备注
在 .NET Framework 2.0 版中，未在用户代码中处理的 AppDomainUnloadedException 具有以下作用：
如果线程是在托管代码中启动的，则该线程终止。未处理异常不能终止应用程序。
如果任务正在 ThreadPool 线程中执行，则该任务终止，且该线程返回线程池。未处理异常不能终止应用程序。
如果线程是在非托管代码中启动的（如主应用程序线程），则该线程终止。允许未处理异常继续，并且操作系统终止应用程序。
AppDomainUnloadedException 使用值为 0x80131014 的 HRESULT COR_E_APPDOMAINUNLOADED。
有关 AppDomainUnloadedException 实例的初始属性值列表，请参见 AppDomainUnloadedException 构造函数。
示例
本节包含两个代码示例。第一个示例演示不同线程中的 AppDomainUnloadedException 的作用，第二个示例演示如何卸载基本应用程序域。
示例 1
下面的代码示例定义一个 TestClass 类和一个 Example 类，前者可以跨应用程序域边界进行封送，后者包含一个 static（在 Visual Basic 中为 Shared）ThreadProc 方法。ThreadProc 方法创建一个应用程序域，在该域中创建一个 TestClass 对象，并调用卸载正在执行的域的 TestClass 的方法，引发 AppDomainUnloadedException 异常。
TestClass 方法在 ThreadPool 线程和普通线程未进行异常处理的情况下执行，演示了未处理异常可终止任务或线程但不会终止应用程序。然后，该方法在主应用程序线程进行异常处理和不进行异常处理两种情况下执行，演示了未处理异常会终止应用程序。
Imports System
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()
'
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()
*/
示例 2
下面的代码示例创建一个应用程序域并将其卸载，演示了对已卸载的域进行后续访问尝试会引发 AppDomainUnloadedException 异常。
Imports System
Imports System.Reflection
Imports System.Security.Policy 'for evidence object
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 'Main
End Class 'ADUnload
using System;
using System.Reflection;
using System.Security.Policy; //for evidence object
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.");
}
}
}
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." );
}
}
import System.*;
import System.Reflection.*;
import System.Security.Policy.*; //for evidence object
class ADUnload
{
public static void main(String[] args)
{
// Create evidence for the new appdomain.
Evidence adEvidence = AppDomain.get_CurrentDomain().get_Evidence();
// Create the new application domain.
AppDomain domain = AppDomain.CreateDomain("MyDomain", adEvidence);
Console.WriteLine("Host domain: "
+ AppDomain.get_CurrentDomain().get_FriendlyName());
Console.WriteLine("child domain: " + domain.get_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.get_FriendlyName());
}
catch (AppDomainUnloadedException e) {
Console.WriteLine("The appdomain MyDomain does not exist.");
}
} //main
} //ADUnload
继承层次结构
System.Object
System.Exception
System.SystemException
System.AppDomainUnloadedException
线程安全
此类型的任何公共静态（Visual Basic 中的 Shared）成员都是线程安全的，但不保证所有实例成员都是线程安全的。
平台
Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition
.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。
版本信息
.NET Framework
受以下版本支持：2.0、1.1、1.0
.NET Compact Framework
受以下版本支持：2.0
请参见
参考
AppDomainUnloadedException 成员
System 命名空间
AppDomain 类
Exception