CountdownEvent CountdownEvent CountdownEvent CountdownEvent Class

Definición

Representa una primitiva de sincronización que está señalada cuando su recuento alcanza el valor cero.Represents a synchronization primitive that is signaled when its count reaches zero.

public ref class CountdownEvent : IDisposable
[System.Runtime.InteropServices.ComVisible(false)]
public class CountdownEvent : IDisposable
type CountdownEvent = class
    interface IDisposable
Public Class CountdownEvent
Implements IDisposable
Herencia
CountdownEventCountdownEventCountdownEventCountdownEvent
Atributos
Implementaciones

Ejemplos

El ejemplo siguiente muestra cómo usar un CountdownEvent:The following example shows how to use a CountdownEvent:

using System;
using System.Collections.Concurrent;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

class Example
{
    static async Task Main()
    {
        // Initialize a queue and a CountdownEvent
        ConcurrentQueue<int> queue = new ConcurrentQueue<int>(Enumerable.Range(0, 10000));
        CountdownEvent cde = new CountdownEvent(10000); // initial count = 10000

        // This is the logic for all queue consumers
        Action consumer = () =>
        {
            int local;
            // decrement CDE count once for each element consumed from queue
            while (queue.TryDequeue(out local)) cde.Signal();
        };

        // Now empty the queue with a couple of asynchronous tasks
        Task t1 = Task.Factory.StartNew(consumer);
        Task t2 = Task.Factory.StartNew(consumer);

        // And wait for queue to empty by waiting on cde
        cde.Wait(); // will return when cde count reaches 0

        Console.WriteLine("Done emptying queue.  InitialCount={0}, CurrentCount={1}, IsSet={2}",
            cde.InitialCount, cde.CurrentCount, cde.IsSet);

        // Proper form is to wait for the tasks to complete, even if you that their work
        // is done already.
        await Task.WhenAll(t1, t2);

        // Resetting will cause the CountdownEvent to un-set, and resets InitialCount/CurrentCount
        // to the specified value
        cde.Reset(10);

        // AddCount will affect the CurrentCount, but not the InitialCount
        cde.AddCount(2);

        Console.WriteLine("After Reset(10), AddCount(2): InitialCount={0}, CurrentCount={1}, IsSet={2}",
            cde.InitialCount, cde.CurrentCount, cde.IsSet);

        // Now try waiting with cancellation
        CancellationTokenSource cts = new CancellationTokenSource();
        cts.Cancel(); // cancels the CancellationTokenSource
        try
        {
            cde.Wait(cts.Token);
        }
        catch (OperationCanceledException)
        {
            Console.WriteLine("cde.Wait(preCanceledToken) threw OCE, as expected");
        }
        finally
        {
           cts.Dispose();
        }
        // It's good to release a CountdownEvent when you're done with it.
        cde.Dispose();
    }
}
// The example displays the following output:
//    Done emptying queue.  InitialCount=10000, CurrentCount=0, IsSet=True
//    After Reset(10), AddCount(2): InitialCount=10, CurrentCount=12, IsSet=False
//    cde.Wait(preCanceledToken) threw OCE, as expected
Imports System.Collections.Concurrent
Imports System.Linq
Imports System.Threading
Imports System.Threading.Tasks

Module Example
    Sub Main()
        ' Initialize a queue and a CountdownEvent
        Dim queue As New ConcurrentQueue(Of Integer)(Enumerable.Range(0, 10000))
        Dim cde As New CountdownEvent(10000)
        ' initial count = 10000
        ' This is the logic for all queue consumers
        Dim consumer As Action =
            Sub()
                Dim local As Integer
                ' decrement CDE count once for each element consumed from queue
                While queue.TryDequeue(local)
                    cde.Signal()
                End While
            End Sub

        ' Now empty the queue with a couple of asynchronous tasks
        Dim t1 As Task = Task.Factory.StartNew(consumer)
        Dim t2 As Task = Task.Factory.StartNew(consumer)

        ' And wait for queue to empty by waiting on cde
        cde.Wait()
        ' will return when cde count reaches 0
        Console.WriteLine("Done emptying queue. InitialCount={0}, CurrentCount={1}, IsSet={2}", cde.InitialCount, cde.CurrentCount, cde.IsSet)

        ' Proper form is to wait for the tasks to complete, even if you know that their work
        ' is done already.
        Task.WaitAll(t1, t2)

        ' Resetting will cause the CountdownEvent to un-set, and resets InitialCount/CurrentCount
        ' to the specified value
        cde.Reset(10)

        ' AddCount will affect the CurrentCount, but not the InitialCount
        cde.AddCount(2)

        Console.WriteLine("After Reset(10), AddCount(2): InitialCount={0}, CurrentCount={1}, IsSet={2}", cde.InitialCount, cde.CurrentCount, cde.IsSet)

        ' Now try waiting with cancellation
        Dim cts As New CancellationTokenSource()
        cts.Cancel()
        ' cancels the CancellationTokenSource
        Try
            cde.Wait(cts.Token)
        Catch generatedExceptionName As OperationCanceledException
            Console.WriteLine("cde.Wait(preCanceledToken) threw OCE, as expected")
        Finally
           cts.Dispose()
        End Try

        ' It's good to release a CountdownEvent when you're done with it.
        cde.Dispose()
    End Sub
End Module
' The example displays the following output:
'    Done emptying queue.  InitialCount=10000, CurrentCount=0, IsSet=True
'    After Reset(10), AddCount(2): InitialCount=10, CurrentCount=12, IsSet=False
'    cde.Wait(preCanceledToken) threw OCE, as expected

Constructores

CountdownEvent(Int32) CountdownEvent(Int32) CountdownEvent(Int32) CountdownEvent(Int32)

Inicializa una nueva instancia de la clase CountdownEvent con el recuento especificado.Initializes a new instance of CountdownEvent class with the specified count.

Propiedades

CurrentCount CurrentCount CurrentCount CurrentCount

Obtiene el número de señales restantes necesario para establecer el evento.Gets the number of remaining signals required to set the event.

InitialCount InitialCount InitialCount InitialCount

Obtiene los números de señales que se necesitan inicialmente para establecer el evento.Gets the numbers of signals initially required to set the event.

IsSet IsSet IsSet IsSet

Indica si el recuento actual del objeto CountdownEvent ha llegado a cero.Indicates whether the CountdownEvent object's current count has reached zero.

WaitHandle WaitHandle WaitHandle WaitHandle

Obtiene un objeto WaitHandle que se usa para esperar a que se establezca el evento.Gets a WaitHandle that is used to wait for the event to be set.

Métodos

AddCount() AddCount() AddCount() AddCount()

Incrementa en uno el recuento actual de CountdownEvent.Increments the CountdownEvent's current count by one.

AddCount(Int32) AddCount(Int32) AddCount(Int32) AddCount(Int32)

Incrementa en un valor especificado el recuento actual de CountdownEvent.Increments the CountdownEvent's current count by a specified value.

Dispose() Dispose() Dispose() Dispose()

Libera todos los recursos usados por la instancia actual de la clase CountdownEvent.Releases all resources used by the current instance of the CountdownEvent class.

Dispose(Boolean) Dispose(Boolean) Dispose(Boolean) Dispose(Boolean)

Libera los recursos no administrados utilizados por el objeto CountdownEvent y, de forma opcional, libera los recursos administrados.Releases the unmanaged resources used by the CountdownEvent, and optionally releases the managed resources.

Equals(Object) Equals(Object) Equals(Object) Equals(Object)

Determina si el objeto especificado es igual al objeto actual.Determines whether the specified object is equal to the current object.

(Inherited from Object)
GetHashCode() GetHashCode() GetHashCode() GetHashCode()

Sirve como la función hash predeterminada.Serves as the default hash function.

(Inherited from Object)
GetType() GetType() GetType() GetType()

Obtiene el Type de la instancia actual.Gets the Type of the current instance.

(Inherited from Object)
MemberwiseClone() MemberwiseClone() MemberwiseClone() MemberwiseClone()

Crea una copia superficial del Object actual.Creates a shallow copy of the current Object.

(Inherited from Object)
Reset() Reset() Reset() Reset()

Restablece CurrentCount en el valor de InitialCount.Resets the CurrentCount to the value of InitialCount.

Reset(Int32) Reset(Int32) Reset(Int32) Reset(Int32)

Restablece la propiedad InitialCount según un valor especificado.Resets the InitialCount property to a specified value.

Signal() Signal() Signal() Signal()

Registra una señal con CountdownEvent y disminuye el valor de CurrentCount.Registers a signal with the CountdownEvent, decrementing the value of CurrentCount.

Signal(Int32) Signal(Int32) Signal(Int32) Signal(Int32)

Registra varias señales con CountdownEvent reduciendo el valor de CurrentCount según la cantidad especificada.Registers multiple signals with the CountdownEvent, decrementing the value of CurrentCount by the specified amount.

ToString() ToString() ToString() ToString()

Devuelve una cadena que representa el objeto actual.Returns a string that represents the current object.

(Inherited from Object)
TryAddCount() TryAddCount() TryAddCount() TryAddCount()

Intenta incrementar CurrentCount en uno.Attempts to increment CurrentCount by one.

TryAddCount(Int32) TryAddCount(Int32) TryAddCount(Int32) TryAddCount(Int32)

Intenta incrementar CurrentCount en un valor especificado.Attempts to increment CurrentCount by a specified value.

Wait() Wait() Wait() Wait()

Bloquea el subproceso actual hasta que se establezca el objeto CountdownEvent.Blocks the current thread until the CountdownEvent is set.

Wait(CancellationToken) Wait(CancellationToken) Wait(CancellationToken) Wait(CancellationToken)

Bloquea el subproceso actual hasta que se establezca el objeto CountdownEvent, mientras se observa un token CancellationToken.Blocks the current thread until the CountdownEvent is set, while observing a CancellationToken.

Wait(Int32) Wait(Int32) Wait(Int32) Wait(Int32)

Bloquea el subproceso actual hasta que se establezca el objeto CountdownEvent, usando un entero de 32 bits con signo para medir el tiempo de espera.Blocks the current thread until the CountdownEvent is set, using a 32-bit signed integer to measure the timeout.

Wait(Int32, CancellationToken) Wait(Int32, CancellationToken) Wait(Int32, CancellationToken) Wait(Int32, CancellationToken)

Bloquea el subproceso actual hasta que se establezca el objeto CountdownEvent, usando un entero de 32 bits con signo para medir el tiempo de espera, mientras se observa un token CancellationToken.Blocks the current thread until the CountdownEvent is set, using a 32-bit signed integer to measure the timeout, while observing a CancellationToken.

Wait(TimeSpan) Wait(TimeSpan) Wait(TimeSpan) Wait(TimeSpan)

Bloquea el subproceso actual hasta que se establezca el objeto CountdownEvent, usando un objeto TimeSpan para medir el tiempo de espera.Blocks the current thread until the CountdownEvent is set, using a TimeSpan to measure the timeout.

Wait(TimeSpan, CancellationToken) Wait(TimeSpan, CancellationToken) Wait(TimeSpan, CancellationToken) Wait(TimeSpan, CancellationToken)

Bloquea el subproceso actual hasta que se establezca el objeto CountdownEvent, usando un objeto TimeSpan para medir el tiempo de espera, mientras se observa un token CancellationToken.Blocks the current thread until the CountdownEvent is set, using a TimeSpan to measure the timeout, while observing a CancellationToken.

Se aplica a

Seguridad para subprocesos

Todos los miembros públicos y protegidos de CountdownEvent son seguros para subprocesos y se pueden usar simultáneamente desde varios subprocesos, con la excepción de Dispose(), que debe usarse solo cuando todas las operaciones en el CountdownEvent haya completado y Reset(), que solo debe usarse cuando otros subprocesos no tienen acceso a los eventos.All public and protected members of CountdownEvent are thread-safe and may be used concurrently from multiple threads, with the exception of Dispose(), which must only be used when all other operations on the CountdownEvent have completed, and Reset(), which should only be used when no other threads are accessing the event.

Consulte también: