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ThreadAbortException Class

The exception that is thrown when a call is made to the Abort method. This class cannot be inherited.

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

'Declaration
<SerializableAttribute> _
<ComVisibleAttribute(True)> _
Public NotInheritable Class ThreadAbortException
	Inherits SystemException
'Usage
Dim instance As ThreadAbortException

/** @attribute SerializableAttribute() */ 
/** @attribute ComVisibleAttribute(true) */ 
public final class ThreadAbortException extends SystemException
SerializableAttribute 
ComVisibleAttribute(true) 
public final class ThreadAbortException extends SystemException

When a call is made to the Abort method to destroy a thread, the common language runtime throws a ThreadAbortException. ThreadAbortException is a special exception that can be caught, but it will automatically be raised again at the end of the catch block. When this exception is raised, the runtime executes all the finally blocks before ending the thread. Since the thread can do an unbounded computation in the finally blocks, or call Thread.ResetAbort to cancel the abort, there is no guarantee that the thread will ever end. If you want to wait until the aborted thread has ended, you can call the Thread.Join method. Join is a blocking call that does not return until the thread actually stops executing.

NoteNote

When the common language runtime (CLR) stops background threads, after all foreground threads in a managed executable have ended, it does not use System.Threading.Thread.Abort. Therefore, you cannot use ThreadAbortException to detect when background threads are being terminated by the CLR.

ThreadAbortException uses the HRESULT COR_E_THREADABORTED, which has the value 0x80131530.

NoteNote

The value of the inherited Data property is always a null reference (Nothing in Visual Basic).

The following example demonstrates aborting a thread. The thread that receives the ThreadAbortException uses the ResetAbort method to cancel the abort request and continue executing.

Imports System
Imports System.Threading
Imports System.Security.Permissions


Public Class ThreadWork
   Public Shared Sub DoWork()
      Try
         Dim i As Integer
         For i = 0 To 99
            Console.WriteLine("Thread - working.")
            Thread.Sleep(100)
         Next i
      Catch e As ThreadAbortException
         Console.WriteLine("Thread - caught ThreadAbortException - resetting.")
         Console.WriteLine("Exception message: {0}", e.Message)
         Thread.ResetAbort()
      End Try
      Console.WriteLine("Thread - still alive and working.")
      Thread.Sleep(1000)
      Console.WriteLine("Thread - finished working.")
   End Sub 'DoWork
End Class 'ThreadWork


Class ThreadAbortTest
   Public Shared Sub Main()
      Dim myThreadDelegate As New ThreadStart(AddressOf ThreadWork.DoWork)
      Dim myThread As New Thread(myThreadDelegate)
      myThread.Start()
      Thread.Sleep(100)
      Console.WriteLine("Main - aborting my thread.")
      myThread.Abort()
      myThread.Join()
      Console.WriteLine("Main ending.")
   End Sub 'Main
End Class 'ThreadAbortTest

import System.*;
import System.Threading.*;
import System.Security.Permissions.*;

public class ThreadWork
{
    public static void DoWork()
    {
        try {
            for (int i = 0; i < 100; i++) {
                Console.WriteLine("Thread - working.");
                System.Threading.Thread.Sleep(100);
            }
        }
        catch (ThreadAbortException e) {
            Console.WriteLine("Thread - caught ThreadAbortException"
                + " - resetting.");
            Console.WriteLine("Exception message: {0}", e.get_Message());
            System.Threading.Thread.ResetAbort();
        }
        Console.WriteLine("Thread - still alive and working.");
        System.Threading.Thread.Sleep(1000);
        Console.WriteLine("Thread - finished working.");
    } //DoWork
} //ThreadWork

class ThreadAbortTest
{
    public static void main(String[] args)
    {
        ThreadStart myThreadDelegate = new ThreadStart(ThreadWork.DoWork);
        System.Threading.Thread myThread =
            new System.Threading.Thread(myThreadDelegate);
        myThread.Start();
        System.Threading.Thread.Sleep(100);
        Console.WriteLine("main - aborting my thread.");
        myThread.Abort();
        myThread.Join();
        Console.WriteLine("main ending.");
    } //main
} //ThreadAbortTest

This code produces the following output:

 Thread - working.
 Main - aborting my thread.
 Thread - caught ThreadAbortException - resetting.
 Exception message: Thread was being aborted.
 Thread - still alive and working.
 Thread - finished working.
 Main ending.

System.Object
   System.Exception
     System.SystemException
      System.Threading.ThreadAbortException

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

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

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

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0

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