TaskCompletionSourceExtensions

Overview

TaskCompletionSourceExtensions provides extension methods for the TaskCompletionSource and TaskCompletionSource<T> types.

To forward the result of one Task to another, call TryCompleteFromCompletedTask.

TryCompleteFromEventArgs can be used to help interoperate with the Event-based Asynchronous Pattern.

The remaining methods TrySetResultWithBackgroundContinuations, TrySetCanceledWithBackgroundContinuations, and TrySetExceptionWithBackgroundContinuations all attempt to transition the underlying Task to the appropriate state, but execute Task continuations on a thread pool thread, even if they were attached using TaskContinuationOperations.ExecuteSynchronously. This is necessary if you are completing a task while holding a lock.

API

// Provides extension methods for TaskCompletionSource.
public static class TaskCompletionSourceExtensions
{
  // Attempts to complete a TaskCompletionSource, propagating the completion of "task".
  public static bool TryCompleteFromCompletedTask<TResult, TSourceResult>(this TaskCompletionSource<TResult> @this, Task<TSourceResult> task) where TSourceResult : TResult;

  // Attempts to complete a TaskCompletionSource, propagating the completion of "task".
  public static bool TryCompleteFromCompletedTask(this TaskCompletionSource @this, Task task);

  // Attempts to complete a TaskCompletionSource, propogating the completion of "eventArgs".
  public static bool TryCompleteFromEventArgs<TResult>(this TaskCompletionSource<TResult> @this, AsyncCompletedEventArgs eventArgs, Func<TResult> getResult);

  // Attempts to complete a TaskCompletionSource, propogating the completion of "eventArgs".
  public static bool TryCompleteFromEventArgs(this TaskCompletionSource @this, AsyncCompletedEventArgs eventArgs);

  // Attempts to complete a TaskCompletionSource with the specified value, forcing all continuations onto a threadpool thread even if they specified ExecuteSynchronously.
  public static void TrySetResultWithBackgroundContinuations<TResult>(this TaskCompletionSource<TResult> @this, TResult result);

  // Attempts to complete a TaskCompletionSource, forcing all continuations onto a threadpool thread even if they specified ExecuteSynchronously.
  public static void TrySetResultWithBackgroundContinuations(this TaskCompletionSource @this);

  // Attempts to complete a TaskCompletionSource as canceled, forcing all continuations onto a threadpool thread even if they specified ExecuteSynchronously.
  public static void TrySetCanceledWithBackgroundContinuations<TResult>(this TaskCompletionSource<TResult> @this);

  // Attempts to complete a TaskCompletionSource as canceled, forcing all continuations onto a threadpool thread even if they specified ExecuteSynchronously.
  public static void TrySetCanceledWithBackgroundContinuations(this TaskCompletionSource @this);

  // Attempts to complete a TaskCompletionSource as faulted, forcing all continuations onto a threadpool thread even if they specified ExecuteSynchronously.
  public static void TrySetExceptionWithBackgroundContinuations<TResult>(this TaskCompletionSource<TResult> @this, Exception exception);

  // Attempts to complete a TaskCompletionSource as faulted, forcing all continuations onto a threadpool thread even if they specified ExecuteSynchronously.
  public static void TrySetExceptionWithBackgroundContinuations(this TaskCompletionSource @this, Exception exception);

  // Attempts to complete a TaskCompletionSource as faulted, forcing all continuations onto a threadpool thread even if they specified ExecuteSynchronously.
  public static void TrySetExceptionWithBackgroundContinuations<TResult>(this TaskCompletionSource<TResult> @this, IEnumerable<Exception> exceptions);

  // Attempts to complete a TaskCompletionSource as faulted, forcing all continuations onto a threadpool thread even if they specified ExecuteSynchronously.
  public static void TrySetExceptionWithBackgroundContinuations(this TaskCompletionSource @this, IEnumerable<Exception> exceptions);
}

Platform Support

The full API is supported on all platforms.