RegisteredWaitHandle.Unregister(WaitHandle) Método

Definición

Cancela una operación de espera registrada y emitida por el método RegisterWaitForSingleObject(WaitHandle, WaitOrTimerCallback, Object, UInt32, Boolean).Cancels a registered wait operation issued by the RegisterWaitForSingleObject(WaitHandle, WaitOrTimerCallback, Object, UInt32, Boolean) method.

public:
 bool Unregister(System::Threading::WaitHandle ^ waitObject);
public bool Unregister (System.Threading.WaitHandle? waitObject);
public bool Unregister (System.Threading.WaitHandle waitObject);
[System.Runtime.InteropServices.ComVisible(true)]
public bool Unregister (System.Threading.WaitHandle waitObject);
member this.Unregister : System.Threading.WaitHandle -> bool
[<System.Runtime.InteropServices.ComVisible(true)>]
member this.Unregister : System.Threading.WaitHandle -> bool
Public Function Unregister (waitObject As WaitHandle) As Boolean

Parámetros

waitObject
WaitHandle

WaitHandle que hay que marcar.The WaitHandle to be signaled.

Devoluciones

Boolean

true si la función se realiza correctamente; en caso contrario, false.true if the function succeeds; otherwise, false.

Atributos

Ejemplos

En el ejemplo siguiente se muestra cómo utilizar el Unregister método para anular el registro de una tarea si se produjo una devolución de llamada porque se señaló el identificador de espera.The following example shows how to use the Unregister method to unregister a task if a callback occurred because the wait handle was signaled.

En el ejemplo también se muestra cómo usar el RegisterWaitForSingleObject método para ejecutar un método de devolución de llamada especificado cuando se señala un identificador de espera especificado.The example also shows how to use the RegisterWaitForSingleObject method to execute a specified callback method when a specified wait handle is signaled. En este ejemplo, el método de devolución de llamada es WaitProc y el identificador de espera es AutoResetEvent .In this example, the callback method is WaitProc, and the wait handle is an AutoResetEvent.

En el ejemplo se define una TaskInfo clase que contiene la información que se pasa a la devolución de llamada cuando se ejecuta.The example defines a TaskInfo class to hold the information that is passed to the callback when it executes. En el ejemplo se crea un TaskInfo objeto y se le asignan algunos datos de cadena.The example creates a TaskInfo object and assigns it some string data. El RegisteredWaitHandle devuelto por el RegisterWaitForSingleObject método se asigna al Handle campo del TaskInfo objeto para que el método de devolución de llamada tenga acceso a RegisteredWaitHandle .The RegisteredWaitHandle that is returned by the RegisterWaitForSingleObject method is assigned to the Handle field of the TaskInfo object so that the callback method has access to the RegisteredWaitHandle.

Además de especificar TaskInfo como el objeto que se va a pasar al método de devolución de llamada, la llamada al RegisterWaitForSingleObject método especifica el AutoResetEvent que la tarea esperará, un WaitOrTimerCallback delegado que representa el WaitProc método de devolución de llamada, un intervalo de tiempo de espera de un segundo y varias devoluciones de llamada.In addition to specifying TaskInfo as the object to pass to the callback method, the call to the RegisterWaitForSingleObject method specifies the AutoResetEvent that the task will wait for, a WaitOrTimerCallback delegate that represents the WaitProc callback method, a one second time-out interval, and multiple callbacks.

Cuando el subproceso principal señala a AutoResetEvent llamando a su Set método, WaitOrTimerCallback se invoca al delegado.When the main thread signals the AutoResetEvent by calling its Set method, the WaitOrTimerCallback delegate is invoked. El WaitProc método prueba RegisteredWaitHandle para determinar si se ha producido un tiempo de espera.The WaitProc method tests RegisteredWaitHandle to determine whether a time-out occurred. Si se invocó la devolución de llamada porque se señaló el identificador de espera, el WaitProc método anula el registro de RegisteredWaitHandle y detiene las devoluciones de llamada adicionales.If the callback was invoked because the wait handle was signaled, the WaitProc method unregisters the RegisteredWaitHandle, stopping additional callbacks. En el caso de un tiempo de espera, la tarea continúa esperando.In the case of a time-out, the task continues to wait. El WaitProc método finaliza mediante la impresión de un mensaje en la consola.The WaitProc method ends by printing a message to the console.

using namespace System;
using namespace System::Threading;

// TaskInfo contains data that will be passed to the callback
// method.
public ref class TaskInfo
{
public:
   TaskInfo()
   {
      Handle = nullptr;
      OtherInfo = "default";
   }

   RegisteredWaitHandle^ Handle;
   String^ OtherInfo;
};

ref class Example
{
public:

   // The callback method executes when the registered wait times out,
   // or when the WaitHandle (in this case AutoResetEvent) is signaled.
   // WaitProc unregisters the WaitHandle the first time the event is 
   // signaled.
   static void WaitProc( Object^ state, bool timedOut )
   {
      
      // The state Object must be cast to the correct type, because the
      // signature of the WaitOrTimerCallback delegate specifies type
      // Object.
      TaskInfo^ ti = static_cast<TaskInfo^>(state);
      String^ cause = "TIMED OUT";
      if (  !timedOut )
      {
         cause = "SIGNALED";
         
         // If the callback method executes because the WaitHandle is
         // signaled, stop future execution of the callback method
         // by unregistering the WaitHandle.
         if ( ti->Handle != nullptr )
                  ti->Handle->Unregister( nullptr );
      }

      Console::WriteLine( "WaitProc( {0}) executes on thread {1}; cause = {2}.", ti->OtherInfo, Thread::CurrentThread->GetHashCode(), cause );
   }

};

int main()
{
   
   // The main thread uses AutoResetEvent to signal the
   // registered wait handle, which executes the callback
   // method.
   AutoResetEvent^ ev = gcnew AutoResetEvent( false );
   TaskInfo^ ti = gcnew TaskInfo;
   ti->OtherInfo = "First task";
   
   // The TaskInfo for the task includes the registered wait
   // handle returned by RegisterWaitForSingleObject.  This
   // allows the wait to be terminated when the object has
   // been signaled once (see WaitProc).
   ti->Handle = ThreadPool::RegisterWaitForSingleObject( ev, gcnew WaitOrTimerCallback( Example::WaitProc ), ti, 1000, false );
   
   // The main thread waits three seconds, to demonstrate the
   // time-outs on the queued thread, and then signals.
   Thread::Sleep( 3100 );
   Console::WriteLine( "Main thread signals." );
   ev->Set();
   
   // The main thread sleeps, which should give the callback
   // method time to execute.  If you comment out this line, the
   // program usually ends before the ThreadPool thread can execute.
   Thread::Sleep( 1000 );
   
   // If you start a thread yourself, you can wait for it to end
   // by calling Thread::Join.  This option is not available with 
   // thread pool threads.
   return 0;
}

using System;
using System.Threading;

// TaskInfo contains data that will be passed to the callback
// method.
public class TaskInfo {
    public RegisteredWaitHandle Handle = null;
    public string OtherInfo = "default";
}

public class Example {
    public static void Main(string[] args) {
        // The main thread uses AutoResetEvent to signal the
        // registered wait handle, which executes the callback
        // method.
        AutoResetEvent ev = new AutoResetEvent(false);

        TaskInfo ti = new TaskInfo();
        ti.OtherInfo = "First task";
        // The TaskInfo for the task includes the registered wait
        // handle returned by RegisterWaitForSingleObject.  This
        // allows the wait to be terminated when the object has
        // been signaled once (see WaitProc).
        ti.Handle = ThreadPool.RegisterWaitForSingleObject(
            ev,
            new WaitOrTimerCallback(WaitProc),
            ti,
            1000,
            false
        );

        // The main thread waits three seconds, to demonstrate the
        // time-outs on the queued thread, and then signals.
        Thread.Sleep(3100);
        Console.WriteLine("Main thread signals.");
        ev.Set();

        // The main thread sleeps, which should give the callback
        // method time to execute.  If you comment out this line, the
        // program usually ends before the ThreadPool thread can execute.
        Thread.Sleep(1000);
        // If you start a thread yourself, you can wait for it to end
        // by calling Thread.Join.  This option is not available with 
        // thread pool threads.
    }
   
    // The callback method executes when the registered wait times out,
    // or when the WaitHandle (in this case AutoResetEvent) is signaled.
    // WaitProc unregisters the WaitHandle the first time the event is 
    // signaled.
    public static void WaitProc(object state, bool timedOut) {
        // The state object must be cast to the correct type, because the
        // signature of the WaitOrTimerCallback delegate specifies type
        // Object.
        TaskInfo ti = (TaskInfo) state;

        string cause = "TIMED OUT";
        if (!timedOut) {
            cause = "SIGNALED";
            // If the callback method executes because the WaitHandle is
            // signaled, stop future execution of the callback method
            // by unregistering the WaitHandle.
            if (ti.Handle != null)
                ti.Handle.Unregister(null);
        } 

        Console.WriteLine("WaitProc( {0} ) executes on thread {1}; cause = {2}.",
            ti.OtherInfo, 
            Thread.CurrentThread.GetHashCode().ToString(), 
            cause
        );
    }
}
Imports System.Threading

' TaskInfo contains data that will be passed to the callback
' method.
Public Class TaskInfo
    public Handle As RegisteredWaitHandle = Nothing
    public OtherInfo As String = "default"
End Class

Public Class Example

    <MTAThread> _
    Public Shared Sub Main()
        ' The main thread uses AutoResetEvent to signal the
        ' registered wait handle, which executes the callback
        ' method.
        Dim ev As New AutoResetEvent(false)

        Dim ti As New TaskInfo()
        ti.OtherInfo = "First task"
        ' The TaskInfo for the task includes the registered wait
        ' handle returned by RegisterWaitForSingleObject.  This
        ' allows the wait to be terminated when the object has
        ' been signaled once (see WaitProc).
        ti.Handle = ThreadPool.RegisterWaitForSingleObject( _
            ev, _
            New WaitOrTimerCallback(AddressOf WaitProc), _
            ti, _
            1000, _
            false _
        )

        ' The main thread waits about three seconds, to demonstrate 
        ' the time-outs on the queued task, and then signals.
        Thread.Sleep(3100)
        Console.WriteLine("Main thread signals.")
        ev.Set()

        ' The main thread sleeps, which should give the callback
        ' method time to execute.  If you comment out this line, the
        ' program usually ends before the ThreadPool thread can execute.
        Thread.Sleep(1000)
        ' If you start a thread yourself, you can wait for it to end
        ' by calling Thread.Join.  This option is not available with 
        ' thread pool threads.
    End Sub
   
    ' The callback method executes when the registered wait times out,
    ' or when the WaitHandle (in this case AutoResetEvent) is signaled.
    ' WaitProc unregisters the WaitHandle the first time the event is 
    ' signaled.
    Public Shared Sub WaitProc(state As Object, timedOut As Boolean)
        ' The state object must be cast to the correct type, because the
        ' signature of the WaitOrTimerCallback delegate specifies type
        ' Object.
        Dim ti As TaskInfo = CType(state, TaskInfo)

        Dim cause As String = "TIMED OUT"
        If Not timedOut Then
            cause = "SIGNALED"
            ' If the callback method executes because the WaitHandle is
            ' signaled, stop future execution of the callback method
            ' by unregistering the WaitHandle.
            If Not ti.Handle Is Nothing Then
                ti.Handle.Unregister(Nothing)
            End If
        End If 

        Console.WriteLine("WaitProc( {0} ) executes on thread {1}; cause = {2}.", _
            ti.OtherInfo, _
            Thread.CurrentThread.GetHashCode().ToString(), _
            cause _
        )
    End Sub
End Class

Comentarios

Si waitObject se especifica, solo se indica si RegisteredWaitHandle se anula correctamente el registro del.If waitObject is specified, it is signaled only if the RegisteredWaitHandle is successfully unregistered. Si un método de devolución de llamada está en curso cuando se Unregister ejecuta, waitObject no se señala hasta que se completa el método de devolución de llamada.If a callback method is in progress when Unregister executes, waitObject is not signaled until the callback method completes. En concreto, si se ejecuta un método de devolución de llamada Unregister , waitObject no se señala hasta que se completa ese método de devolución de llamada.In particular, if a callback method executes Unregister, waitObject is not signaled until that callback method completes.

Se aplica a