TaskScheduler TaskScheduler TaskScheduler TaskScheduler Class

Definición

Representa un objeto que administra el trabajo de bajo nivel de poner en cola tareas en los subprocesos.Represents an object that handles the low-level work of queuing tasks onto threads.

public ref class TaskScheduler abstract
public abstract class TaskScheduler
type TaskScheduler = class
Public MustInherit Class TaskScheduler
Herencia
TaskSchedulerTaskSchedulerTaskSchedulerTaskScheduler

Ejemplos

En el siguiente ejemplo se toma de la ejemplos de programación en paralelo con .NET Framework 4 en el sitio Web de MSDN Code Gallery.The following example is taken from the Samples for Parallel Programming with the .NET Framework 4 on the MSDN Code Gallery Web site. Crea a un programador de tareas personalizado que limita el número de subprocesos usados por la aplicación.It creates a custom task scheduler that limits the number of threads used by the app. A continuación, inicia dos conjuntos de tareas y muestra información acerca de la tarea y el subproceso en que se ejecuta la tarea.It then launches two sets of tasks and displays information about the task and the thread on which the task is executing.

using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

class Example
{
   static void Main()
   {
       // Create a scheduler that uses two threads. 
       LimitedConcurrencyLevelTaskScheduler lcts = new LimitedConcurrencyLevelTaskScheduler(2);
       List<Task> tasks = new List<Task>();
       
       // Create a TaskFactory and pass it our custom scheduler. 
       TaskFactory factory = new TaskFactory(lcts);
       CancellationTokenSource cts = new CancellationTokenSource();
       
       // Use our factory to run a set of tasks. 
       Object lockObj = new Object();
       int outputItem = 0;
       
       for (int tCtr = 0; tCtr <= 4; tCtr++) {
          int iteration = tCtr;
          Task t = factory.StartNew(() => {
                                       for (int i = 0; i < 1000; i++) {
                                          lock (lockObj) {
                                             Console.Write("{0} in task t-{1} on thread {2}   ", 
                                                           i, iteration, Thread.CurrentThread.ManagedThreadId);
                                             outputItem++;
                                             if (outputItem % 3 == 0)
                                                Console.WriteLine();
                                          }
                                       }                   
                                    }, cts.Token);
          tasks.Add(t);                      
      }
      // Use it to run a second set of tasks.                       
      for (int tCtr = 0; tCtr <= 4; tCtr++) {
         int iteration = tCtr;
         Task t1 = factory.StartNew(() => {
                                       for (int outer = 0; outer <= 10; outer++) {
                                          for (int i = 0x21; i <= 0x7E; i++) {
                                             lock (lockObj) {
                                                Console.Write("'{0}' in task t1-{1} on thread {2}   ", 
                                                              Convert.ToChar(i), iteration, Thread.CurrentThread.ManagedThreadId);
                                                outputItem++;
                                                if (outputItem % 3 == 0)
                                                   Console.WriteLine();
                                             } 
                                          }
                                       }                                           
                                    }, cts.Token);           
         tasks.Add(t1);
      }
      
      // Wait for the tasks to complete before displaying a completion message.
      Task.WaitAll(tasks.ToArray());
      cts.Dispose();
      Console.WriteLine("\n\nSuccessful completion.");
   }
}

// Provides a task scheduler that ensures a maximum concurrency level while 
// running on top of the thread pool.
public class LimitedConcurrencyLevelTaskScheduler : TaskScheduler
{
   // Indicates whether the current thread is processing work items.
   [ThreadStatic]
   private static bool _currentThreadIsProcessingItems;

  // The list of tasks to be executed 
   private readonly LinkedList<Task> _tasks = new LinkedList<Task>(); // protected by lock(_tasks)

   // The maximum concurrency level allowed by this scheduler. 
   private readonly int _maxDegreeOfParallelism;

   // Indicates whether the scheduler is currently processing work items. 
   private int _delegatesQueuedOrRunning = 0;

   // Creates a new instance with the specified degree of parallelism. 
   public LimitedConcurrencyLevelTaskScheduler(int maxDegreeOfParallelism)
   {
       if (maxDegreeOfParallelism < 1) throw new ArgumentOutOfRangeException("maxDegreeOfParallelism");
       _maxDegreeOfParallelism = maxDegreeOfParallelism;
   }

   // Queues a task to the scheduler. 
   protected sealed override void QueueTask(Task task)
   {
      // Add the task to the list of tasks to be processed.  If there aren't enough 
      // delegates currently queued or running to process tasks, schedule another. 
       lock (_tasks)
       {
           _tasks.AddLast(task);
           if (_delegatesQueuedOrRunning < _maxDegreeOfParallelism)
           {
               ++_delegatesQueuedOrRunning;
               NotifyThreadPoolOfPendingWork();
           }
       }
   }

   // Inform the ThreadPool that there's work to be executed for this scheduler. 
   private void NotifyThreadPoolOfPendingWork()
   {
       ThreadPool.UnsafeQueueUserWorkItem(_ =>
       {
           // Note that the current thread is now processing work items.
           // This is necessary to enable inlining of tasks into this thread.
           _currentThreadIsProcessingItems = true;
           try
           {
               // Process all available items in the queue.
               while (true)
               {
                   Task item;
                   lock (_tasks)
                   {
                       // When there are no more items to be processed,
                       // note that we're done processing, and get out.
                       if (_tasks.Count == 0)
                       {
                           --_delegatesQueuedOrRunning;
                           break;
                       }

                       // Get the next item from the queue
                       item = _tasks.First.Value;
                       _tasks.RemoveFirst();
                   }

                   // Execute the task we pulled out of the queue
                   base.TryExecuteTask(item);
               }
           }
           // We're done processing items on the current thread
           finally { _currentThreadIsProcessingItems = false; }
       }, null);
   }

   // Attempts to execute the specified task on the current thread. 
   protected sealed override bool TryExecuteTaskInline(Task task, bool taskWasPreviouslyQueued)
   {
       // If this thread isn't already processing a task, we don't support inlining
       if (!_currentThreadIsProcessingItems) return false;

       // If the task was previously queued, remove it from the queue
       if (taskWasPreviouslyQueued) 
          // Try to run the task. 
          if (TryDequeue(task)) 
            return base.TryExecuteTask(task);
          else
             return false; 
       else 
          return base.TryExecuteTask(task);
   }

   // Attempt to remove a previously scheduled task from the scheduler. 
   protected sealed override bool TryDequeue(Task task)
   {
       lock (_tasks) return _tasks.Remove(task);
   }

   // Gets the maximum concurrency level supported by this scheduler. 
   public sealed override int MaximumConcurrencyLevel { get { return _maxDegreeOfParallelism; } }

   // Gets an enumerable of the tasks currently scheduled on this scheduler. 
   protected sealed override IEnumerable<Task> GetScheduledTasks()
   {
       bool lockTaken = false;
       try
       {
           Monitor.TryEnter(_tasks, ref lockTaken);
           if (lockTaken) return _tasks;
           else throw new NotSupportedException();
       }
       finally
       {
           if (lockTaken) Monitor.Exit(_tasks);
       }
   }
}
// The following is a portion of the output from a single run of the example:
//    'T' in task t1-4 on thread 3   'U' in task t1-4 on thread 3   'V' in task t1-4 on thread 3   
//    'W' in task t1-4 on thread 3   'X' in task t1-4 on thread 3   'Y' in task t1-4 on thread 3   
//    'Z' in task t1-4 on thread 3   '[' in task t1-4 on thread 3   '\' in task t1-4 on thread 3   
//    ']' in task t1-4 on thread 3   '^' in task t1-4 on thread 3   '_' in task t1-4 on thread 3   
//    '`' in task t1-4 on thread 3   'a' in task t1-4 on thread 3   'b' in task t1-4 on thread 3   
//    'c' in task t1-4 on thread 3   'd' in task t1-4 on thread 3   'e' in task t1-4 on thread 3   
//    'f' in task t1-4 on thread 3   'g' in task t1-4 on thread 3   'h' in task t1-4 on thread 3   
//    'i' in task t1-4 on thread 3   'j' in task t1-4 on thread 3   'k' in task t1-4 on thread 3   
//    'l' in task t1-4 on thread 3   'm' in task t1-4 on thread 3   'n' in task t1-4 on thread 3   
//    'o' in task t1-4 on thread 3   'p' in task t1-4 on thread 3   ']' in task t1-2 on thread 4   
//    '^' in task t1-2 on thread 4   '_' in task t1-2 on thread 4   '`' in task t1-2 on thread 4   
//    'a' in task t1-2 on thread 4   'b' in task t1-2 on thread 4   'c' in task t1-2 on thread 4   
//    'd' in task t1-2 on thread 4   'e' in task t1-2 on thread 4   'f' in task t1-2 on thread 4   
//    'g' in task t1-2 on thread 4   'h' in task t1-2 on thread 4   'i' in task t1-2 on thread 4   
//    'j' in task t1-2 on thread 4   'k' in task t1-2 on thread 4   'l' in task t1-2 on thread 4   
//    'm' in task t1-2 on thread 4   'n' in task t1-2 on thread 4   'o' in task t1-2 on thread 4   
//    'p' in task t1-2 on thread 4   'q' in task t1-2 on thread 4   'r' in task t1-2 on thread 4   
//    's' in task t1-2 on thread 4   't' in task t1-2 on thread 4   'u' in task t1-2 on thread 4   
//    'v' in task t1-2 on thread 4   'w' in task t1-2 on thread 4   'x' in task t1-2 on thread 4   
//    'y' in task t1-2 on thread 4   'z' in task t1-2 on thread 4   '{' in task t1-2 on thread 4   
//    '|' in task t1-2 on thread 4   '}' in task t1-2 on thread 4   '~' in task t1-2 on thread 4   
//    'q' in task t1-4 on thread 3   'r' in task t1-4 on thread 3   's' in task t1-4 on thread 3   
//    't' in task t1-4 on thread 3   'u' in task t1-4 on thread 3   'v' in task t1-4 on thread 3   
//    'w' in task t1-4 on thread 3   'x' in task t1-4 on thread 3   'y' in task t1-4 on thread 3   
//    'z' in task t1-4 on thread 3   '{' in task t1-4 on thread 3   '|' in task t1-4 on thread 3  
Imports System.Collections.Generic
Imports System.Threading
Imports System.Threading.Tasks

Module Example
   Sub Main()
      ' Create a scheduler that uses two threads. 
      Dim lcts As New LimitedConcurrencyLevelTaskScheduler(2)
      Dim tasks As New List(Of Task)()
      
      ' Create a TaskFactory and pass it our custom scheduler. 
      Dim factory As New TaskFactory(lcts)
      Dim cts As New CancellationTokenSource()
      
      ' Use our factory to run a set of tasks. 
      Dim objLock As New Object()      
      Dim outputItem As Integer 
      For tCtr As Integer = 0 To 4
         Dim iteration As Integer = tCtr
         Dim t As Task = factory.StartNew(Sub()
                                             For i As Integer = 1 To 1000
                                                SyncLock objLock
                                                   Console.Write("{0} in task t-{1} on thread {2}   ", 
                                                   i, iteration, Thread.CurrentThread.ManagedThreadId)
                                                   outputItem += 1
                                                   If outputItem Mod 3 = 0 Then Console.WriteLine()
                                                End SyncLock
                                             Next 
                                          End Sub,
                                cts.Token)
         tasks.Add(t)
      Next 
      ' Use it to run a second set of tasks.                       
      For tCtr As Integer = 0 To 4
         Dim iteration As Integer = tCtr
         Dim t1 As Task = factory.StartNew(Sub()
                                              For outer As Integer = 0 To 10
                                                 For i As Integer = &h21 To &h7E
                                                    SyncLock objLock
                                                       Console.Write("'{0}' in task t1-{1} on thread {2}   ", 
                                                                     Convert.ToChar(i), iteration, Thread.CurrentThread.ManagedThreadId)
                                                       outputItem += 1
                                                       If outputItem Mod 3 = 0 Then Console.WriteLine()
                                                    End SyncLock 
                                                 Next     
                                              Next                                           
                                           End Sub,
                                cts.Token)           
         tasks.Add(t1)
      Next
      
      ' Wait for the tasks to complete before displaying a completion message.
      Task.WaitAll(tasks.ToArray())
      cts.Dispose()
      Console.WriteLine(vbCrLf + vbCrLf + "Successful completion.")
   End Sub 
End Module

' Provides a task scheduler that ensures a maximum concurrency level while 
' running on top of the thread pool.
Public Class LimitedConcurrencyLevelTaskScheduler : Inherits TaskScheduler
   ' Indicates whether the current thread is processing work items.
   <ThreadStatic()> Private Shared _currentThreadIsProcessingItems As Boolean 
   
   ' The list of tasks to be executed 
   Private ReadOnly _tasks As LinkedList(Of Task) = New LinkedList(Of Task)() 
   
   'The maximum concurrency level allowed by this scheduler. 
   Private ReadOnly _maxDegreeOfParallelism As Integer 
   
   ' Indicates whether the scheduler is currently processing work items. 
   Private _delegatesQueuedOrRunning As Integer = 0 ' protected by lock(_tasks)
   
   ' Creates a new instance with the specified degree of parallelism. 
   Public Sub New(ByVal maxDegreeOfParallelism As Integer)
      If (maxDegreeOfParallelism < 1) Then 
         Throw New ArgumentOutOfRangeException("maxDegreeOfParallelism")
      End If
         _maxDegreeOfParallelism = maxDegreeOfParallelism
   End Sub 

   ' Queues a task to the scheduler. 
   Protected Overrides Sub QueueTask(ByVal t As Task)
      ' Add the task to the list of tasks to be processed.  If there aren't enough 
      ' delegates currently queued or running to process tasks, schedule another. 
      SyncLock (_tasks)
         _tasks.AddLast(t)
         If (_delegatesQueuedOrRunning < _maxDegreeOfParallelism) Then
            _delegatesQueuedOrRunning = _delegatesQueuedOrRunning + 1
            NotifyThreadPoolOfPendingWork()
         End If 
      End SyncLock 
   End Sub 
   
   ' Inform the ThreadPool that there's work to be executed for this scheduler. 
   Private Sub NotifyThreadPoolOfPendingWork()
   
      ThreadPool.UnsafeQueueUserWorkItem(Sub()
                                            ' Note that the current thread is now processing work items. 
                                            ' This is necessary to enable inlining of tasks into this thread.
                                            _currentThreadIsProcessingItems = True 
                                            Try 
                                               ' Process all available items in the queue. 
                                               While (True)
                                                  Dim item As Task
                                                  SyncLock (_tasks)
                                                     ' When there are no more items to be processed, 
                                                     ' note that we're done processing, and get out. 
                                                     If (_tasks.Count = 0) Then
                                                        _delegatesQueuedOrRunning = _delegatesQueuedOrRunning - 1
                                                        Exit While 
                                                     End If 
   
                                                     ' Get the next item from the queue
                                                     item = _tasks.First.Value
                                                     _tasks.RemoveFirst()
                                                  End SyncLock 
   
                                                  ' Execute the task we pulled out of the queue 
                                                  MyBase.TryExecuteTask(item)
                                               End While 
                                               ' We're done processing items on the current thread 
                                            Finally
                                               _currentThreadIsProcessingItems = False 
                                            End Try 
                                         End Sub,
                                    Nothing)
   End Sub 
   
   ' Attempts to execute the specified task on the current thread. 
   Protected Overrides Function TryExecuteTaskInline(ByVal t As Task, 
                                                     ByVal taskWasPreviouslyQueued As Boolean) As Boolean 
      ' If this thread isn't already processing a task, we don't support inlining 
      If (Not _currentThreadIsProcessingItems) Then 
         Return False 
      End If 
   
      ' If the task was previously queued, remove it from the queue 
      If (taskWasPreviouslyQueued) Then
         ' Try to run the task. 
         If TryDequeue(t) Then 
            Return MyBase.TryExecuteTask(t)
         Else
            Return False 
         End If     
      Else 
         Return MyBase.TryExecuteTask(t)
      End If   
   End Function 
   
   ' Attempt to remove a previously scheduled task from the scheduler. 
   Protected Overrides Function TryDequeue(ByVal t As Task) As Boolean 
      SyncLock (_tasks)
         Return _tasks.Remove(t)
      End SyncLock 
   End Function 
   
   ' Gets the maximum concurrency level supported by this scheduler. 
   Public Overrides ReadOnly Property MaximumConcurrencyLevel As Integer 
      Get 
         Return _maxDegreeOfParallelism
      End Get 
   End Property 
   
   ' Gets an enumerable of the tasks currently scheduled on this scheduler. 
   Protected Overrides Function GetScheduledTasks() As IEnumerable(Of Task)
      Dim lockTaken As Boolean = False 
      Try
         Monitor.TryEnter(_tasks, lockTaken)
         If (lockTaken) Then 
            Return _tasks.ToArray()
         Else 
            Throw New NotSupportedException()
         End If 
      Finally 
         If (lockTaken) Then
            Monitor.Exit(_tasks)
         End If 
      End Try 
   End Function 
End Class 
' The following is a portion of the output from a single run of the example:
'    'T' in task t1-4 on thread 3   'U' in task t1-4 on thread 3   'V' in task t1-4 on thread 3   
'    'W' in task t1-4 on thread 3   'X' in task t1-4 on thread 3   'Y' in task t1-4 on thread 3   
'    'Z' in task t1-4 on thread 3   '[' in task t1-4 on thread 3   '\' in task t1-4 on thread 3   
'    ']' in task t1-4 on thread 3   '^' in task t1-4 on thread 3   '_' in task t1-4 on thread 3   
'    '`' in task t1-4 on thread 3   'a' in task t1-4 on thread 3   'b' in task t1-4 on thread 3   
'    'c' in task t1-4 on thread 3   'd' in task t1-4 on thread 3   'e' in task t1-4 on thread 3   
'    'f' in task t1-4 on thread 3   'g' in task t1-4 on thread 3   'h' in task t1-4 on thread 3   
'    'i' in task t1-4 on thread 3   'j' in task t1-4 on thread 3   'k' in task t1-4 on thread 3   
'    'l' in task t1-4 on thread 3   'm' in task t1-4 on thread 3   'n' in task t1-4 on thread 3   
'    'o' in task t1-4 on thread 3   'p' in task t1-4 on thread 3   ']' in task t1-2 on thread 4   
'    '^' in task t1-2 on thread 4   '_' in task t1-2 on thread 4   '`' in task t1-2 on thread 4   
'    'a' in task t1-2 on thread 4   'b' in task t1-2 on thread 4   'c' in task t1-2 on thread 4   
'    'd' in task t1-2 on thread 4   'e' in task t1-2 on thread 4   'f' in task t1-2 on thread 4   
'    'g' in task t1-2 on thread 4   'h' in task t1-2 on thread 4   'i' in task t1-2 on thread 4   
'    'j' in task t1-2 on thread 4   'k' in task t1-2 on thread 4   'l' in task t1-2 on thread 4   
'    'm' in task t1-2 on thread 4   'n' in task t1-2 on thread 4   'o' in task t1-2 on thread 4   
'    'p' in task t1-2 on thread 4   'q' in task t1-2 on thread 4   'r' in task t1-2 on thread 4   
'    's' in task t1-2 on thread 4   't' in task t1-2 on thread 4   'u' in task t1-2 on thread 4   
'    'v' in task t1-2 on thread 4   'w' in task t1-2 on thread 4   'x' in task t1-2 on thread 4   
'    'y' in task t1-2 on thread 4   'z' in task t1-2 on thread 4   '{' in task t1-2 on thread 4   
'    '|' in task t1-2 on thread 4   '}' in task t1-2 on thread 4   '~' in task t1-2 on thread 4   
'    'q' in task t1-4 on thread 3   'r' in task t1-4 on thread 3   's' in task t1-4 on thread 3   
'    't' in task t1-4 on thread 3   'u' in task t1-4 on thread 3   'v' in task t1-4 on thread 3   
'    'w' in task t1-4 on thread 3   'x' in task t1-4 on thread 3   'y' in task t1-4 on thread 3   
'    'z' in task t1-4 on thread 3   '{' in task t1-4 on thread 3   '|' in task t1-4 on thread 3  

Además, varios programadores de tareas de ejemplo están disponibles en la Galería de código: Ejemplos de programación paralela con .NET Framework 4.In addition, several sample task schedulers are available on Code Gallery: Samples for Parallel Programming with the .NET Framework 4.

Comentarios

Una instancia de la TaskScheduler clase representa un programador de tareas.An instance of the TaskScheduler class represents a task scheduler. Un programador de tareas asegura que se ejecuta el trabajo de una tarea.A task scheduler ensures that the work of a task is eventually executed.

El programador de tareas predeterminado está basado en el grupo de subprocesos .NET Framework 4, que proporciona robo de trabajo para el equilibrio de carga, inyección/retirada de subprocesos, a fin de obtener el máximo resultado y un buen rendimiento en general.The default task scheduler is based on the .NET Framework 4 thread pool, which provides work-stealing for load-balancing, thread injection/retirement for maximum throughput, and overall good performance. Debería ser suficiente para la mayoría de los escenarios.It should be sufficient for most scenarios.

La TaskScheduler clase también actúa como el punto de extensión para toda la lógica de programación personalizable.The TaskScheduler class also serves as the extension point for all customizable scheduling logic. Esto incluye mecanismos, como cómo programar una tarea para su ejecución y las tareas programadas de cómo se debe exponer a los depuradores.This includes mechanisms such as how to schedule a task for execution, and how scheduled tasks should be exposed to debuggers. Si necesita funcionalidad especial, puede crear a un programador personalizado y habilitarlo para tareas específicas o las consultas.If you require special functionality, you can create a custom scheduler and enable it for specific tasks or queries.

En este tema:In this topic:
El programador de tareas predeterminado y el grupo de subprocesosThe default task scheduler and the thread pool
La cola global frente a las colas localesThe global queue vs. local queues
Robo de trabajoWork stealing
Tareas de ejecución prolongadaLong-running tasks
Inclusión de tareasTask inlining
Especifica un contexto de sincronizaciónSpecifying a synchronization context

El programador de tareas predeterminado y el grupo de subprocesosThe default task scheduler and the thread pool

El programador predeterminado para la biblioteca TPL y PLINQ usa el grupo de subprocesos de .NET Framework, que viene representado por la ThreadPool (clase), para poner en cola y ejecutar el trabajo.The default scheduler for the Task Parallel Library and PLINQ uses the .NET Framework thread pool, which is represented by the ThreadPool class, to queue and execute work. El grupo de subprocesos usa la información suministrada por el Task tipo para admitir el paralelismo específico (unidades efímeras de trabajo) que en paralelo las tareas y las consultas a menudo representan de forma eficaz.The thread pool uses the information that is provided by the Task type to efficiently support the fine-grained parallelism (short-lived units of work) that parallel tasks and queries often represent.

La cola global frente a las colas localesThe global queue vs. local queues

El grupo de subprocesos mantiene la cola de subprocesos en cada dominio de aplicación de trabajo de un global FIFO (primero en salir).The thread pool maintains a global FIFO (first-in, first-out) work queue for threads in each application domain. Cada vez que un programa llama a la ThreadPool.QueueUserWorkItem (o ThreadPool.UnsafeQueueUserWorkItem) método, el trabajo es poner en esta cola compartida y finalmente sale de la cola hacia el subproceso siguiente que está disponible.Whenever a program calls the ThreadPool.QueueUserWorkItem (or ThreadPool.UnsafeQueueUserWorkItem) method, the work is put on this shared queue and eventually de-queued onto the next thread that becomes available. A partir de .NET Framework 4, esta cola se ha mejorado para usar un algoritmo sin bloqueo que se parezca a la ConcurrentQueue<T> clase.Starting with the .NET Framework 4, this queue has been improved to use a lock-free algorithm that resembles the ConcurrentQueue<T> class. Mediante esta implementación sin bloqueo, el grupo de subprocesos emplea menos tiempo en poner y sacar elementos de trabajo de las colas.By using this lock-free implementation, the thread pool spends less time when it queues and de-queues work items. Esta ventaja de rendimiento está disponible para todos los programas que usan el grupo de subprocesos.This performance benefit is available to all programs that use the thread pool.

Las tareas de nivel superior, que son tareas que no se crean en el contexto de otra tarea, se colocan en la cola global igual que cualquier otro elemento de trabajo.Top-level tasks, which are tasks that are not created in the context of another task, are put on the global queue just like any other work item. Sin embargo, las tareas anidadas o secundarias, que se crean en el contexto de otra tarea, se controlan de forma bastante distinta.However, nested or child tasks, which are created in the context of another task, are handled quite differently. Una tarea secundaria o anidada se coloca en una cola local que es específica del subproceso en el que la tarea primaria se está ejecutando.A child or nested task is put on a local queue that is specific to the thread on which the parent task is executing. La tarea primaria puede ser una tarea de nivel superior o también puede ser el elemento secundario de otra tarea.The parent task may be a top-level task or it also may be the child of another task. Cuando este subproceso está listo para más trabajo, primero busca en la cola local.When this thread is ready for more work, it first looks in the local queue. Si hay elementos de trabajo esperando, se puede tener acceso a ellos rápidamente.If work items are waiting there, they can be accessed quickly. Se tiene acceso a las colas locales en el orden último en salir (LIFO) para conservar la localidad de memoria caché y reducir la contención.The local queues are accessed in last-in, first-out order (LIFO) to preserve cache locality and reduce contention. Para obtener más información acerca de las tareas secundarias y anidadas, vea adjuntas y tareas secundarias desasociadas.For more information about child tasks and nested tasks, see Attached and Detached Child Tasks.

El uso de colas locales no sólo reduce la presión en la cola global, sino que también aprovecha las ventajas de la localidad de los datos.The use of local queues not only reduces pressure on the global queue, but also takes advantage of data locality. Los elementos de trabajo locales en cola con frecuencia las estructuras de datos de referencia que se encuentran físicamente próximos entre sí en memoria.Work items in the local queue frequently reference data structures that are physically near one another in memory. En estos casos, los datos ya están en la memoria caché después de la primera tarea se ha ejecutado y se puede acceder rápidamente.In these cases, the data is already in the cache after the first task has run and can be accessed quickly. Ambos Parallel LINQ (PLINQ) y Parallel ampliamente de clases usa tareas anidadas y tareas secundarias y conseguir aumentos significativos de velocidad mediante las colas de trabajo local.Both Parallel LINQ (PLINQ) and the Parallel class use nested tasks and child tasks extensively, and achieve significant speedups by using the local work queues.

Robo de trabajoWork stealing

A partir de .NET Framework 4, el grupo de subprocesos también incluye un algoritmo de robo de trabajo para ayudar a asegurarse de que no se encuentra ningún subproceso inactivo mientras otros todavía tienen trabajo en sus colas.Starting with the .NET Framework 4, the thread pool also features a work-stealing algorithm to help make sure that no threads are sitting idle while others still have work in their queues. Cuando un subproceso ThreadPool está listo para más trabajo, examina primero el encabezado de la cola local, a continuación, en la cola global y después en las colas locales de otros subprocesos.When a thread-pool thread is ready for more work, it first looks at the head of its local queue, then in the global queue, and then in the local queues of other threads. Si encuentra un elemento de trabajo en la cola local de otro subproceso, aplica primero heurística para asegurarse de que puede ejecutar el trabajo eficazmente.If it finds a work item in the local queue of another thread, it first applies heuristics to make sure that it can run the work efficiently. Si es posible, quita de la cola el elemento de trabajo de la cola (en orden FIFO).If it can, it de-queues the work item from the tail (in FIFO order). Esto reduce la contención en cada cola local y mantiene la situación de los datos.This reduces contention on each local queue and preserves data locality. Esta arquitectura permite el equilibrio de carga de grupo de subprocesos funcione de manera más eficaz que versiones anteriores.This architecture helps the thread pool load-balance work more efficiently than past versions did.

Tareas de ejecución prolongadaLong-running tasks

Tal vez le interese evitar explícitamente que una tarea se coloque en una cola local.You may want to explicitly prevent a task from being put on a local queue. Por ejemplo, puede saber que un elemento de trabajo determinado se ejecutará durante un tiempo relativamente largo y es probable que bloquee el resto de los elementos de trabajo de la cola local.For example, you may know that a particular work item will run for a relatively long time and is likely to block all other work items on the local queue. En este caso, puede especificar la opción System.Threading.Tasks.TaskCreationOptions, que proporciona una sugerencia al programador que le indica que tal vez es necesario un subproceso adicional para que la tarea no bloquee el progreso de otros subprocesos o elementos de trabajo de la cola local.In this case, you can specify the System.Threading.Tasks.TaskCreationOptions option, which provides a hint to the scheduler that an additional thread might be required for the task so that it does not block the forward progress of other threads or work items on the local queue. Con esta opción evita el grupo de subprocesos por completo, incluidas las colas globales y locales.By using this option you avoid the thread pool completely, including the global and local queues.

Inclusión de tareasTask inlining

En algunos casos, cuando un Task se esperando, se puede ejecutar sincrónicamente en el subproceso que realiza la operación de espera.In some cases when a Task is waited on, it may be executed synchronously on the thread that is performing the wait operation. Esto mejora el rendimiento evitando la necesidad de un subproceso adicional y en su lugar utilizando el subproceso existente, que en caso contrario, se habría bloqueado.This enhances performance by preventing the need for an additional thread and instead using the existing thread, which would have blocked otherwise. Para evitar errores debido a la reentrada, inclusión de tareas solo se produce cuando se encuentra el destino de la espera en cola local del subproceso pertinente.To prevent errors due to reentrancy, task inlining only occurs when the wait target is found in the relevant thread's local queue.

Especifica un contexto de sincronizaciónSpecifying a synchronization context

Puede utilizar el método TaskScheduler.FromCurrentSynchronizationContext para especificar que una tarea se debería programar para ejecutarse en un subproceso determinado.You can use the TaskScheduler.FromCurrentSynchronizationContext method to specify that a task should be scheduled to run on a particular thread. Esto es útil en marcos como Windows Forms y Windows Presentation Foundation, donde el acceso a los objetos de interfaz de usuario está restringido a menudo para el código que se está ejecutando en el mismo subproceso en el que se creó el objeto UI.This is useful in frameworks such as Windows Forms and Windows Presentation Foundation where access to user interface objects is often restricted to code that is running on the same thread on which the UI object was created.

En el ejemplo siguiente se usa el TaskScheduler.FromCurrentSynchronizationContext método en una aplicación de Windows Presentation Foundation (WPF) para programar una tarea en el mismo subproceso donde se creó el control de interfaz de usuario.The following example uses the TaskScheduler.FromCurrentSynchronizationContext method in a Windows Presentation Foundation (WPF) app to schedule a task on the same thread that the user interface (UI) control was created on. En el ejemplo se crea un mosaico de imágenes que se seleccionan aleatoriamente de un directorio especificado.The example creates a mosaic of images that are randomly selected from a specified directory. Los objetos de WPF se usan para cargar y cambiar el tamaño de las imágenes.The WPF objects are used to load and resize the images. Los píxeles sin procesar, a continuación, se pasan a una tarea que usa un For bucle para escribir los datos de píxeles en una matriz grande de un byte.The raw pixels are then passed to a task that uses a For loop to write the pixel data into a large single-byte array. Se necesita ninguna sincronización porque no hay dos iconos ocupan los mismos elementos de matriz.No synchronization is required because no two tiles occupy the same array elements. Los iconos también se pueden escribir en cualquier orden porque su posición se calcula independientemente de cualquier otro icono.The tiles can also be written in any order because their position is calculated independently of any other tile. La matriz de gran tamaño, a continuación, se pasa a una tarea que se ejecuta en el subproceso de interfaz de usuario, donde se cargan los datos de píxeles en un control de imagen.The large array is then passed to a task that runs on the UI thread, where the pixel data is loaded into an Image control.

El ejemplo mueve los datos fuera del subproceso de interfaz de usuario, lo modifica mediante el uso de bucles paralelos y Task objetos y, a continuación, se pasa a una tarea que se ejecuta en el subproceso de interfaz de usuario.The example moves data off the UI thread, modifies it by using parallel loops and Task objects, and then passes it back to a task that runs on the UI thread. Este enfoque es útil cuando tiene que usar la biblioteca TPL para realizar operaciones que no son compatibles con la API de WPF, o que no son lo suficientemente rápido.This approach is useful when you have to use the Task Parallel Library to perform operations that either are not supported by the WPF API, or are not sufficiently fast. Otra forma de crear un mosaico de la imagen en WPF es usar un System.Windows.Controls.WrapPanel controlar y agregar imágenes a él.Another way to create an image mosaic in WPF is to use a System.Windows.Controls.WrapPanel control and add images to it. El WrapPanel controla el trabajo de colocar los iconos.The WrapPanel handles the work of positioning the tiles. Sin embargo, este trabajo solo puede realizarse en el subproceso de interfaz de usuario.However, this work can only be performed on the UI thread.

using System;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace WPF_CS1
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        private int fileCount;
        int colCount;
        int rowCount;
        private int tilePixelHeight;
        private int tilePixelWidth;
        private int largeImagePixelHeight;
        private int largeImagePixelWidth;
        private int largeImageStride;
        PixelFormat format;
        BitmapPalette palette = null;

        public MainWindow()
        {
            InitializeComponent();

            // For this example, values are hard-coded to a mosaic of 8x8 tiles.
            // Each tile is 50 pixels high and 66 pixels wide and 32 bits per pixel.
            colCount = 12;
            rowCount = 8;
            tilePixelHeight = 50;
            tilePixelWidth = 66;
            largeImagePixelHeight = tilePixelHeight * rowCount;
            largeImagePixelWidth = tilePixelWidth * colCount;
            largeImageStride = largeImagePixelWidth * (32 / 8);
            this.Width = largeImagePixelWidth + 40;
            image.Width = largeImagePixelWidth;
            image.Height = largeImagePixelHeight;


        }

        private void button_Click(object sender, RoutedEventArgs e)
        {

            // For best results use 1024 x 768 jpg files at 32bpp.
            string[] files = System.IO.Directory.GetFiles(@"C:\Users\Public\Pictures\Sample Pictures\", "*.jpg");

            fileCount = files.Length;
            Task<byte[]>[] images = new Task<byte[]>[fileCount];
            for (int i = 0; i < fileCount; i++)
            {
                int x = i;
                images[x] = Task.Factory.StartNew(() => LoadImage(files[x]));
            }

            // When they've all been loaded, tile them into a single byte array.
            var tiledImage = Task.Factory.ContinueWhenAll(
                images, (i) => TileImages(i));

            // We are currently on the UI thread. Save the sync context and pass it to
            // the next task so that it can access the UI control "image".
            var UISyncContext = TaskScheduler.FromCurrentSynchronizationContext();

            // On the UI thread, put the bytes into a bitmap and
            // display it in the Image control.
            var t3 = tiledImage.ContinueWith((antecedent) =>
            {
                // Get System DPI.
                Matrix m = PresentationSource.FromVisual(Application.Current.MainWindow)
                                            .CompositionTarget.TransformToDevice;
                double dpiX = m.M11;
                double dpiY = m.M22;

                BitmapSource bms = BitmapSource.Create(largeImagePixelWidth,
                    largeImagePixelHeight,
                    dpiX,
                    dpiY,
                    format,
                    palette, //use default palette
                    antecedent.Result,
                    largeImageStride);
                image.Source = bms;
            }, UISyncContext);
        }

        byte[] LoadImage(string filename)
        {
            // Use the WPF BitmapImage class to load and 
            // resize the bitmap. NOTE: Only 32bpp formats are supported correctly.
            // Support for additional color formats is left as an exercise
            // for the reader. For more information, see documentation for ColorConvertedBitmap.

            BitmapImage bitmapImage = new BitmapImage();
            bitmapImage.BeginInit();
            bitmapImage.UriSource = new Uri(filename);
            bitmapImage.DecodePixelHeight = tilePixelHeight;
            bitmapImage.DecodePixelWidth = tilePixelWidth;
            bitmapImage.EndInit();

            format = bitmapImage.Format;
            int size = (int)(bitmapImage.Height * bitmapImage.Width);
            int stride = (int)bitmapImage.Width * 4;
            byte[] dest = new byte[stride * tilePixelHeight];

            bitmapImage.CopyPixels(dest, stride, 0);

            return dest;
        }

        int Stride(int pixelWidth, int bitsPerPixel)
        {
            return (((pixelWidth * bitsPerPixel + 31) / 32) * 4);
        }

        // Map the individual image tiles to the large image
        // in parallel. Any kind of raw image manipulation can be
        // done here because we are not attempting to access any 
        // WPF controls from multiple threads.
        byte[] TileImages(Task<byte[]>[] sourceImages)
        {
            byte[] largeImage = new byte[largeImagePixelHeight * largeImageStride];
            int tileImageStride = tilePixelWidth * 4; // hard coded to 32bpp

            Random rand = new Random();
            Parallel.For(0, rowCount * colCount, (i) =>
            {
                // Pick one of the images at random for this tile.
                int cur = rand.Next(0, sourceImages.Length);
                byte[] pixels = sourceImages[cur].Result;

                // Get the starting index for this tile.
                int row = i / colCount;
                int col = (int)(i % colCount);
                int idx = ((row * (largeImageStride * tilePixelHeight)) + (col * tileImageStride));

                // Write the pixels for the current tile. The pixels are not contiguous
                // in the array, therefore we have to advance the index by the image stride
                // (minus the stride of the tile) for each scanline of the tile.
                int tileImageIndex = 0;
                for (int j = 0; j < tilePixelHeight; j++)
                {
                    // Write the next scanline for this tile.
                    for (int k = 0; k < tileImageStride; k++)
                    {
                        largeImage[idx++] = pixels[tileImageIndex++];
                    }
                    // Advance to the beginning of the next scanline.
                    idx += largeImageStride - tileImageStride;
                }
            });
            return largeImage;
        }
    }
}
Imports System.Threading.Tasks
Imports System.Windows
Imports System.Windows.Media
Imports System.Windows.Media.Imaging

Partial Public Class MainWindow : Inherits Window
    Dim fileCount As Integer
    Dim colCount As Integer
    Dim rowCount As Integer
    Dim tilePixelHeight As Integer
    Dim tilePixelWidth As Integer
    Dim largeImagePixelHeight As Integer
    Dim largeImagePixelWidth As Integer
    Dim largeImageStride As Integer
    Dim format As PixelFormat
    Dim palette As BitmapPalette = Nothing

    Public Sub New()
        InitializeComponent()

        ' For this example, values are hard-coded to a mosaic of 8x8 tiles.
        ' Each tile Is 50 pixels high and 66 pixels wide and 32 bits per pixel.
        colCount = 12
        rowCount = 8
        tilePixelHeight = 50
        tilePixelWidth = 66
        largeImagePixelHeight = tilePixelHeight * rowCount
        largeImagePixelWidth = tilePixelWidth * colCount
        largeImageStride = largeImagePixelWidth * (32 / 8)
        Me.Width = largeImagePixelWidth + 40
        image.Width = largeImagePixelWidth
        image.Height = largeImagePixelHeight
    End Sub

    Private Sub button_Click(sender As Object, e As RoutedEventArgs) _
        Handles button.Click

        ' For best results use 1024 x 768 jpg files at 32bpp.
        Dim files() As String = System.IO.Directory.GetFiles("C:\Users\Public\Pictures\Sample Pictures\", "*.jpg")

        fileCount = files.Length
        Dim images(fileCount - 1) As Task(Of Byte())
        For i As Integer = 0 To fileCount - 1
            Dim x As Integer = i
            images(x) = Task.Factory.StartNew(Function() LoadImage(files(x)))
        Next

        ' When they have all been loaded, tile them into a single byte array.
        'var tiledImage = Task.Factory.ContinueWhenAll(
        '        images, (i) >= TileImages(i));

        '        Dim tiledImage As Task(Of Byte()) = Task.Factory.ContinueWhenAll(images, Function(i As Task(Of Byte())) TileImages(i))
        Dim tiledImage = Task.Factory.ContinueWhenAll(images, Function(i As Task(Of Byte())()) TileImages(i))
        ' We are currently on the UI thread. Save the sync context and pass it to
        ' the next task so that it can access the UI control "image1".
        Dim UISyncContext = TaskScheduler.FromCurrentSynchronizationContext()

        ' On the UI thread, put the bytes into a bitmap and
        ' display it in the Image control.
        Dim t3 = tiledImage.ContinueWith(Sub(antecedent)
                                             ' Get System DPI.
                                             Dim m As Matrix = PresentationSource.FromVisual(Application.Current.MainWindow).CompositionTarget.TransformToDevice
                                             Dim dpiX As Double = m.M11
                                             Dim dpiY As Double = m.M22

                                             ' Use the default palette in creating the bitmap.
                                             Dim bms As BitmapSource = BitmapSource.Create(largeImagePixelWidth,
                                                                                           largeImagePixelHeight,
                                             dpiX,
                                             dpiY,
                                             format,
                                             palette,
                                             antecedent.Result,
                                             largeImageStride)
                                             image.Source = bms
                                         End Sub, UISyncContext)
    End Sub

    Public Function LoadImage(filename As String) As Byte()
        ' Use the WPF BitmapImage class to load and 
        ' resize the bitmap. NOTE: Only 32bpp formats are supported correctly.
        ' Support for additional color formats Is left as an exercise
        ' for the reader. For more information, see documentation for ColorConvertedBitmap.
        Dim bitmapImage As New BitmapImage()
        bitmapImage.BeginInit()
        bitmapImage.UriSource = New Uri(filename)
        bitmapImage.DecodePixelHeight = tilePixelHeight
        bitmapImage.DecodePixelWidth = tilePixelWidth
        bitmapImage.EndInit()

        format = bitmapImage.Format
        Dim size As Integer = CInt(bitmapImage.Height * bitmapImage.Width)
        Dim stride As Integer = CInt(bitmapImage.Width * 4)
        Dim dest(stride * tilePixelHeight - 1) As Byte

        bitmapImage.CopyPixels(dest, stride, 0)

        Return dest
    End Function

    Function Stride(pixelWidth As Integer, bitsPerPixel As Integer) As Integer
        Return (((pixelWidth * bitsPerPixel + 31) / 32) * 4)
    End Function

    ' Map the individual image tiles to the large image
    ' in parallel. Any kind of raw image manipulation can be
    ' done here because we are Not attempting to access any 
    ' WPF controls from multiple threads.
    Function TileImages(sourceImages As Task(Of Byte())()) As Byte()
        Dim largeImage(largeImagePixelHeight * largeImageStride - 1) As Byte
        Dim tileImageStride As Integer = tilePixelWidth * 4 ' hard coded To 32bpp

        Dim rand As New Random()
        Parallel.For(0, rowCount * colCount, Sub(i)
                                                 ' Pick one of the images at random for this tile.
                                                 Dim cur As Integer = rand.Next(0, sourceImages.Length)
                                                 Dim pixels() As Byte = sourceImages(cur).Result

                                                 ' Get the starting index for this tile.
                                                 Dim row As Integer = i \ colCount
                                                 Dim col As Integer = i Mod colCount
                                                 Dim idx As Integer = ((row * (largeImageStride * tilePixelHeight)) + (col * tileImageStride))

                                                 ' Write the pixels for the current tile. The pixels are Not contiguous
                                                 ' in the array, therefore we have to advance the index by the image stride
                                                 ' (minus the stride of the tile) for each scanline of the tile.
                                                 Dim tileImageIndex As Integer = 0
                                                 For j As Integer = 0 To tilePixelHeight - 1
                                                     ' Write the next scanline for this tile.
                                                     For k As Integer = 0 To tileImageStride - 1
                                                         largeImage(idx) = pixels(tileImageIndex)
                                                         idx += 1
                                                         tileImageIndex += 1
                                                     Next
                                                     ' Advance to the beginning of the next scanline.
                                                     idx += largeImageStride - tileImageStride
                                                 Next
                                             End Sub)
        Return largeImage
    End Function
End Class

Para crear el ejemplo, cree un proyecto de aplicación de WPF en Visual Studio y asígnele el nombre WPF_CS1 (para un C# proyecto de WPF) o WPF_VB1 (para un proyecto de WPF de Visual Basic).To create the example, create a WPF application project in Visual Studio and name it WPF_CS1 (for a C# WPF project) or WPF_VB1 (for a Visual Basic WPF project). A continuación, haga lo siguiente:Then do the following:

  1. En la vista Diseño, arrastre un Image controlar desde la cuadro de herramientas en la esquina superior izquierda de la superficie de diseño.In design view, drag an Image control from the Toolbox onto the upper left corner of the design surface. En el nombre cuadro de texto de la propiedades ventana, el nombre de la "imagen" del control.In the Name textbox of the Properties window, name the control "image".

  2. Arrastre un Button controlar desde la cuadro de herramientas a la parte inferior izquierda de la ventana de la aplicación.Drag a Button control from the Toolbox to the lower left part of the application window. En la vista XAML, especifique la Content propiedad del botón como "Make un mosaico" y especifique su Width propiedad como "100".In XAML view, specify the Content property of the button as "Make a mosaic", and specify its Width property as "100". Conectar el Click evento con el button_Click controlador de eventos definido en el código del ejemplo agregando Click="button_Click" a la <Button> elemento.Connect the Click event with the button_Click event handler defined in the example's code by adding Click="button_Click" to the <Button> element. En el nombre cuadro de texto de la propiedades ventana, el nombre del botón"control".In the Name textbox of the Properties window, name the control "button".

  3. Reemplace todo el contenido del archivo MainWindow.xaml.cs o MainWindow.xaml.vb por el código de este ejemplo.Replace the entire contents of the MainWindow.xaml.cs or MainWindow.xaml.vb file with the code from this example. Para un C# WPF del proyecto, asegúrese de que el nombre del área de trabajo coincide con el nombre del proyecto.For a C# WPF project, make sure that the name of the workspace matches the project name.

  4. El ejemplo lee las imágenes JPEG de un directorio denominado C:\Users\Public\Pictures\Sample Pictures\.The example reads JPEG images from a directory named C:\Users\Public\Pictures\Sample Pictures\. Cree el directorio y coloque algunas imágenes en ella o cambiar la ruta de acceso para hacer referencia a otro directorio que contiene imágenes.Either create the directory and place some images in it, or change the path to refer to some other directory that contains images.

En este ejemplo tiene algunas limitaciones.This example has some limitations. Por ejemplo, se admiten imágenes de sólo 32-bits por píxel; las imágenes en otros formatos están dañadas por la BitmapImage objeto durante la operación de cambio de tamaño.For example, only 32-bits-per-pixel images are supported; images in other formats are corrupted by the BitmapImage object during the resizing operation. Además, las imágenes de origen deben mayores que el tamaño del mosaico.Also, the source images must all be larger than the tile size. Como ejercicio adicional, puede agregar funcionalidad para controlar varios formatos de píxel y tamaños de archivo.As a further exercise, you can add functionality to handle multiple pixel formats and file sizes.

Constructores

TaskScheduler() TaskScheduler() TaskScheduler() TaskScheduler()

Inicializa el TaskScheduler.Initializes the TaskScheduler.

Propiedades

Current Current Current Current

Obtiene el objeto TaskScheduler asociado a la tarea que se está ejecutando actualmente.Gets the TaskScheduler associated with the currently executing task.

Default Default Default Default

Obtiene la instancia predeterminada de TaskScheduler proporcionada por .NET Framework.Gets the default TaskScheduler instance that is provided by the .NET Framework.

Id Id Id Id

Obtiene el identificador único de este TaskScheduler.Gets the unique ID for this TaskScheduler.

MaximumConcurrencyLevel MaximumConcurrencyLevel MaximumConcurrencyLevel MaximumConcurrencyLevel

Indica el nivel de simultaneidad máximo admitido por este TaskScheduler.Indicates the maximum concurrency level this TaskScheduler is able to support.

Métodos

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)
Finalize() Finalize() Finalize() Finalize()

Libera todos los recursos asociados a este programador.Frees all resources associated with this scheduler.

FromCurrentSynchronizationContext() FromCurrentSynchronizationContext() FromCurrentSynchronizationContext() FromCurrentSynchronizationContext()

Crea un TaskScheduler asociado con el SynchronizationContext actual.Creates a TaskScheduler associated with the current SynchronizationContext.

GetHashCode() GetHashCode() GetHashCode() GetHashCode()

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

(Inherited from Object)
GetScheduledTasks() GetScheduledTasks() GetScheduledTasks() GetScheduledTasks()

Solo por compatibilidad con el depurador, genera un enumerable de las instancias de Task que se encuentran actualmente en la cola del programador a la espera de ser ejecutadas.For debugger support only, generates an enumerable of Task instances currently queued to the scheduler waiting to be executed.

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 objeto Object actual.Creates a shallow copy of the current Object.

(Inherited from Object)
QueueTask(Task) QueueTask(Task) QueueTask(Task) QueueTask(Task)

Pone un objeto Task en la cola del programador.Queues a Task to the scheduler.

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

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

(Inherited from Object)
TryDequeue(Task) TryDequeue(Task) TryDequeue(Task) TryDequeue(Task)

Intenta quitar un objeto Task de la cola de este programador.Attempts to dequeue a Task that was previously queued to this scheduler.

TryExecuteTask(Task) TryExecuteTask(Task) TryExecuteTask(Task) TryExecuteTask(Task)

Intenta ejecutar el objeto Task especificado en este programador.Attempts to execute the provided Task on this scheduler.

TryExecuteTaskInline(Task, Boolean) TryExecuteTaskInline(Task, Boolean) TryExecuteTaskInline(Task, Boolean) TryExecuteTaskInline(Task, Boolean)

Determina si el objeto Task especificado puede ejecutarse sincrónicamente en esta llamada y, en caso afirmativo, lo ejecuta.Determines whether the provided Task can be executed synchronously in this call, and if it can, executes it.

Eventos

UnobservedTaskException UnobservedTaskException UnobservedTaskException UnobservedTaskException

Se produce cuando la excepción no observada de un error de la tarea está a punto de desencadenar la directiva de escalado de excepción que, de forma predeterminada, finalizaría el proceso.Occurs when a faulted task's unobserved exception is about to trigger exception escalation policy, which, by default, would terminate the process.

Se aplica a

Seguridad para subprocesos

Todos los miembros de la abstracta TaskScheduler tipo son seguros para subprocesos y se pueden usar desde varios subprocesos simultáneamente.All members of the abstract TaskScheduler type are thread-safe and may be used from multiple threads concurrently.

Consulte también: