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EventResetMode (Enumeración)

Actualización: noviembre 2007

Indica si un objeto EventWaitHandle se restablece automática o manualmente después de recibir una señal.

Espacio de nombres:  System.Threading
Ensamblado:  mscorlib (en mscorlib.dll)

[ComVisibleAttribute(false)]
public enum EventResetMode
/** @attribute ComVisibleAttribute(false) */
public enum EventResetMode
public enum EventResetMode

Nombre de miembroDescripción
s14cz4sk.CFW(es-es,VS.90).gifs14cz4sk.xna(es-es,VS.90).gifAutoResetEl objeto EventWaitHandle, cuando está señalado, se restablece automáticamente después de haber liberado un único subproceso. Si hay ningún subproceso en espera, el objeto EventWaitHandle permanece señalado hasta que un subproceso se bloquea y se restablece después de haber liberado el subproceso.
s14cz4sk.CFW(es-es,VS.90).gifs14cz4sk.xna(es-es,VS.90).gifManualResetEl objeto EventWaitHandle, cuando está señalado, libera todos los subprocesos en espera y permanece señalado hasta que se restablece manualmente.

En el siguiente ejemplo de código se utiliza la sobrecarga del método SignalAndWait(WaitHandle, WaitHandle) para que permitir que el subproceso principal señale un subproceso bloqueado y, después, se espera a que el subproceso finalice una tarea.

En el ejemplo se inician cinco subprocesos y se permite que estos subprocesos se bloqueen en un objeto EventWaitHandle creado con el indicador EventResetMode.AutoReset; después, se libera un subproceso cada vez que el usuario presiona la tecla ENTRAR. A continuación, se ponen otros cinco subprocesos en cola y se liberan todos ellos utilizando un objeto EventWaitHandle creado con el indicador EventResetMode.ManualReset.

using System;
using System.Threading;

public class Example
{
    // The EventWaitHandle used to demonstrate the difference
    // between AutoReset and ManualReset synchronization events.
    //
    private static EventWaitHandle ewh;

    // A counter to make sure all threads are started and
    // blocked before any are released. A Long is used to show
    // the use of the 64-bit Interlocked methods.
    //
    private static long threadCount = 0;

    // An AutoReset event that allows the main thread to block
    // until an exiting thread has decremented the count.
    //
    private static EventWaitHandle clearCount = 
        new EventWaitHandle(false, EventResetMode.AutoReset);

    [MTAThread]
    public static void Main()
    {
        // Create an AutoReset EventWaitHandle.
        //
        ewh = new EventWaitHandle(false, EventResetMode.AutoReset);

        // Create and start five numbered threads. Use the
        // ParameterizedThreadStart delegate, so the thread
        // number can be passed as an argument to the Start 
        // method.
        for (int i = 0; i <= 4; i++)
        {
            Thread t = new Thread(
                new ParameterizedThreadStart(ThreadProc)
            );
            t.Start(i);
        }

        // Wait until all the threads have started and blocked.
        // When multiple threads use a 64-bit value on a 32-bit
        // system, you must access the value through the
        // Interlocked class to guarantee thread safety.
        //
        while (Interlocked.Read(ref threadCount) < 5)
        {
            Thread.Sleep(500);
        }

        // Release one thread each time the user presses ENTER,
        // until all threads have been released.
        //
        while (Interlocked.Read(ref threadCount) > 0)
        {
            Console.WriteLine("Press ENTER to release a waiting thread.");
            Console.ReadLine();

            // SignalAndWait signals the EventWaitHandle, which
            // releases exactly one thread before resetting, 
            // because it was created with AutoReset mode. 
            // SignalAndWait then blocks on clearCount, to 
            // allow the signaled thread to decrement the count
            // before looping again.
            //
            WaitHandle.SignalAndWait(ewh, clearCount);
        }
        Console.WriteLine();

        // Create a ManualReset EventWaitHandle.
        //
        ewh = new EventWaitHandle(false, EventResetMode.ManualReset);

        // Create and start five more numbered threads.
        //
        for(int i=0; i<=4; i++)
        {
            Thread t = new Thread(
                new ParameterizedThreadStart(ThreadProc)
            );
            t.Start(i);
        }

        // Wait until all the threads have started and blocked.
        //
        while (Interlocked.Read(ref threadCount) < 5)
        {
            Thread.Sleep(500);
        }

        // Because the EventWaitHandle was created with
        // ManualReset mode, signaling it releases all the
        // waiting threads.
        //
        Console.WriteLine("Press ENTER to release the waiting threads.");
        Console.ReadLine();
        ewh.Set();

    }

    public static void ThreadProc(object data)
    {
        int index = (int) data;

        Console.WriteLine("Thread {0} blocks.", data);
        // Increment the count of blocked threads.
        Interlocked.Increment(ref threadCount);

        // Wait on the EventWaitHandle.
        ewh.WaitOne();

        Console.WriteLine("Thread {0} exits.", data);
        // Decrement the count of blocked threads.
        Interlocked.Decrement(ref threadCount);

        // After signaling ewh, the main thread blocks on
        // clearCount until the signaled thread has 
        // decremented the count. Signal it now.
        //
        clearCount.Set();
    }
}


import System.*;
import System.Threading.*;

public class Example
{
    // The EventWaitHandle used to demonstrate the difference
    // between AutoReset and ManualReset synchronization events.
    //
    private static EventWaitHandle ewh;

    // A counter to make sure all threads are started and
    // blocked before any are released. A Long is used to show
    // the use of the 64-bit Interlocked methods.
    //
    private static long threadCount = 0;

    // An AutoReset event that allows the main thread to block
    // until an exiting thread has decremented the count.
    //
    private static EventWaitHandle clearCount = new EventWaitHandle(false,
        EventResetMode.AutoReset);

    /** @attribute MTAThread()
     */
    public static void main(String[] args)
    {
        // Create an AutoReset EventWaitHandle.
        //
        ewh = new EventWaitHandle(false, EventResetMode.AutoReset);
        // Create and start five numbered threads. Use the
        // ParameterizedThreadStart delegate, so the thread
        // number can be passed as an argument to the Start 
        // method.
        for (int i = 0; i <= 4; i++) {
            System.Threading.Thread t = new System.Threading.Thread(new 
                ParameterizedThreadStart(ThreadProc));
            t.Start((Int32)i);
        }
        // Wait until all the threads have started and blocked.
        // When multiple threads use a 64-bit value on a 32-bit
        // system, you must access the value through the
        // Interlocked class to guarantee thread safety.
        //
        while (Interlocked.Read(threadCount) < 5) {
            System.Threading.Thread.Sleep(500);
        }
        // Release one thread each time the user presses ENTER,
        // until all threads have been released.
        //
        while (Interlocked.Read(threadCount) > 0) {
            Console.WriteLine("Press ENTER to release a waiting thread.");
            Console.ReadLine();
            // SignalAndWait signals the EventWaitHandle, which
            // releases exactly one thread before resetting, 
            // because it was created with AutoReset mode. 
            // SignalAndWait then blocks on clearCount, to 
            // allow the signaled thread to decrement the count
            // before looping again.
            //
            WaitHandle.SignalAndWait(ewh, clearCount);
        }
        Console.WriteLine();
        // Create a ManualReset EventWaitHandle.
        //
        ewh = new EventWaitHandle(false, EventResetMode.ManualReset);
        // Create and start five more numbered threads.
        //
        for (int i = 0; i <= 4; i++) {
            System.Threading.Thread t = new System.Threading.Thread(new 
                ParameterizedThreadStart(ThreadProc));
            t.Start((Int32)i);
        }
        // Wait until all the threads have started and blocked.
        //
        while (Interlocked.Read(threadCount) < 5) {
            System.Threading.Thread.Sleep(500);
        }
        // Because the EventWaitHandle was created with
        // ManualReset mode, signaling it releases all the
        // waiting threads.
        //
        Console.WriteLine("Press ENTER to release the waiting threads.");
        Console.ReadLine();
        ewh.Set();
    } //main

    public static void ThreadProc(Object data)
    {
        int index = System.Convert.ToInt32(data);

        Console.WriteLine("Thread {0} blocks.", data);
        // Increment the count of blocked threads.
        Interlocked.Increment(threadCount);
        // Wait on the EventWaitHandle.
        ewh.WaitOne();

        Console.WriteLine("Thread {0} exits.", data);
        // Decrement the count of blocked threads.
        Interlocked.Decrement(threadCount);
        // After signaling ewh, the main thread blocks on
        // clearCount until the signaled thread has 
        // decremented the count. Signal it now.
        //
        clearCount.Set();
    } //ThreadProc
} //Example


Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile para Smartphone, Windows Mobile para Pocket PC, Xbox 360

.NET Framework y .NET Compact Framework no admiten todas las versiones de cada plataforma. Para obtener una lista de las versiones compatibles, vea Requisitos de sistema de .NET Framework.

.NET Framework

Compatible con: 3.5, 3.0, 2.0

.NET Compact Framework

Compatible con: 3.5

XNA Framework

Compatible con: 2.0, 1.0
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