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AppDomainUnloadedException Class

The exception that is thrown when an attempt is made to access an unloaded application domain.

System.Object
  System.Exception
    System.SystemException
      System.AppDomainUnloadedException

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

[SerializableAttribute]
[ComVisibleAttribute(true)]
public class AppDomainUnloadedException : SystemException

The AppDomainUnloadedException type exposes the following members.

  NameDescription
Public methodSupported by the XNA FrameworkAppDomainUnloadedException()Initializes a new instance of the AppDomainUnloadedException class.
Public methodSupported by the XNA FrameworkAppDomainUnloadedException(String)Initializes a new instance of the AppDomainUnloadedException class with a specified error message.
Protected methodAppDomainUnloadedException(SerializationInfo, StreamingContext)Initializes a new instance of the AppDomainUnloadedException class with serialized data.
Public methodSupported by the XNA FrameworkAppDomainUnloadedException(String, Exception)Initializes a new instance of the AppDomainUnloadedException class with a specified error message and a reference to the inner exception that is the cause of this exception.
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  NameDescription
Public propertyDataGets a collection of key/value pairs that provide additional user-defined information about the exception. (Inherited from Exception.)
Public propertyHelpLinkGets or sets a link to the help file associated with this exception. (Inherited from Exception.)
Public propertySupported by the XNA FrameworkHResultGets or sets HRESULT, a coded numerical value that is assigned to a specific exception. (Inherited from Exception.)
Public propertySupported by the XNA FrameworkInnerExceptionGets the Exception instance that caused the current exception. (Inherited from Exception.)
Public propertySupported by the XNA FrameworkMessageGets a message that describes the current exception. (Inherited from Exception.)
Public propertySourceGets or sets the name of the application or the object that causes the error. (Inherited from Exception.)
Public propertySupported by the XNA FrameworkStackTraceGets a string representation of the immediate frames on the call stack. (Inherited from Exception.)
Public propertyTargetSiteGets the method that throws the current exception. (Inherited from Exception.)
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  NameDescription
Public methodSupported by the XNA FrameworkEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Protected methodSupported by the XNA FrameworkFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodSupported by the XNA FrameworkGetBaseExceptionWhen overridden in a derived class, returns the Exception that is the root cause of one or more subsequent exceptions. (Inherited from Exception.)
Public methodSupported by the XNA FrameworkGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetObjectDataWhen overridden in a derived class, sets the SerializationInfo with information about the exception. (Inherited from Exception.)
Public methodSupported by the XNA FrameworkGetTypeGets the runtime type of the current instance. (Inherited from Exception.)

In XNA Framework 3.0, this member is inherited from Object.GetType().
Protected methodSupported by the XNA FrameworkMemberwiseCloneCreates a shallow copy of the current Object. (Inherited from Object.)
Public methodSupported by the XNA FrameworkToStringCreates and returns a string representation of the current exception. (Inherited from Exception.)
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  NameDescription
Protected eventSerializeObjectStateOccurs when an exception is serialized to create an exception state object that contains serialized data about the exception. (Inherited from Exception.)
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In the .NET Framework version 2.0, an AppDomainUnloadedException that is not handled in user code has the following effect:

  • If a thread was started in managed code, it is terminated. The unhandled exception is not allowed to terminate the application.

  • If a task is executing on a ThreadPool thread, it is terminated and the thread is returned to the thread pool. The unhandled exception is not allowed to terminate the application.

  • If a thread started in unmanaged code, such as the main application thread, it is terminated. The unhandled exception is allowed to proceed, and the operating system terminates the application.

AppDomainUnloadedException uses the HRESULT COR_E_APPDOMAINUNLOADED, which has the value 0x80131014.

For a list of initial property values for an instance of AppDomainUnloadedException, see the AppDomainUnloadedException constructors.

This section contains two code examples. The first example demonstrates the effects of an AppDomainUnloadedException on various threads, and the second shows elementary application domain unloading.

Example 1

The following code example defines a TestClass class that can be marshaled across application domain boundaries and an Example class containing a static (Shared in Visual Basic) ThreadProc method. The ThreadProc method creates an application domain, creates a TestClass object in the domain, and calls a method of TestClass that unloads the executing domain, causing an AppDomainUnloadedException.

The TestClass method is executed without exception handling from a ThreadPool thread and from an ordinary thread, demonstrating that the unhandled exception terminates the task or thread but not the application. It is then executed with and without exception handling from the main application thread, demonstrating that it terminates the application if not handled.

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()
 */

Example 2

The following code example creates and unloads an application domain, and demonstrates that an AppDomainUnloadedException is thrown on a subsequent attempt to access the unloaded domain.

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.");
		}
		
	}
	
}

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
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