我使用 MSDN 中的LimitedTaskScheduler来捕获所有异常，包括使用 TPL 的其他线程：
public class LimitedConcurrencyLevelTaskScheduler : TaskScheduler
{
/// Whether the current thread is processing work items.
[ThreadStatic]
private static bool currentThreadIsProcessingItems;
/// The list of tasks to be executed.
private readonly LinkedList tasks = new LinkedList(); // protected by lock(tasks)
private readonly ILogger logger;
/// The maximum concurrency level allowed by this scheduler.
private readonly int maxDegreeOfParallelism;
/// Whether the scheduler is currently processing work items.
private int delegatesQueuedOrRunning; // protected by lock(tasks)
public LimitedConcurrencyLevelTaskScheduler(ILogger logger) : this(logger, Environment.ProcessorCount)
{
}
public LimitedConcurrencyLevelTaskScheduler(ILogger logger, int maxDegreeOfParallelism)
{
this.logger = logger;
if (maxDegreeOfParallelism Gets the maximum concurrency level supported by this scheduler.
public override sealed int MaximumConcurrencyLevel
{
get { return maxDegreeOfParallelism; }
}
/// Queues a task to the scheduler.
/// The task to be queued.
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)
{
return;
}
++delegatesQueuedOrRunning;
NotifyThreadPoolOfPendingWork();
}
}
/// Attempts to execute the specified task on the current thread.
/// The task to be executed.
///
/// Whether the task could be executed 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)
{
TryDequeue(task);
}
// Try to run the task.
return TryExecuteTask(task);
}
/// Attempts to remove a previously scheduled task from the scheduler.
/// The task to be removed.
/// Whether the task could be found and removed.
protected sealed override bool TryDequeue(Task task)
{
lock (tasks)
{
return tasks.Remove(task);
}
}
/// Gets an enumerable of the tasks currently scheduled on this scheduler.
/// An enumerable of the tasks currently scheduled.
protected sealed override IEnumerable GetScheduledTasks()
{
var lockTaken = false;
try
{
Monitor.TryEnter(tasks, ref lockTaken);
if (lockTaken)
{
return tasks.ToArray();
}
else
{
throw new NotSupportedException();
}
}
finally
{
if (lockTaken)
{
Monitor.Exit(tasks);
}
}
}
protected virtual void OnTaskFault(AggregateException exception)
{
logger.Error(exception);
}
///
/// Informs the ThreadPool that there's work to be executed for this scheduler.
///
private void NotifyThreadPoolOfPendingWork()
{
ThreadPool.UnsafeQueueUserWorkItem(ExcuteTask, null);
}
private void ExcuteTask(object state)
{
// 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
TryExecuteTask(item);
if (!item.IsFaulted)
{
continue;
}
OnTaskFault(item.Exception);
}
}
finally
{
// We're done processing items on the current thread
currentThreadIsProcessingItems = false;
}
}
}
并且比 TaskScheduler 的“注册”作为默认使用反射：
public static class TaskLogging
{
private const BindingFlags StaticBinding = BindingFlags.Static | BindingFlags.NonPublic;
public static void SetScheduler(TaskScheduler taskScheduler)
{
var field = typeof(TaskScheduler).GetField("s_defaultTaskScheduler", StaticBinding);
field.SetValue(null, taskScheduler);
SetOnTaskFactory(new TaskFactory(taskScheduler));
}
private static void SetOnTaskFactory(TaskFactory taskFactory)
{
var field = typeof(Task).GetField("s_factory", StaticBinding);
field.SetValue(null, taskFactory);
}
}