NotifyTaskCompletion

Overview

The NotifyTaskCompletion types enable using Tasks in situations where you need to support data binding. Properties on the notifier type will update when the task completes.

You can create an INotifyTaskCompletion or INotifyTaskCompletion<TResult> by calling NotifyTaskCompletion.Create and passing in the Task to observe.

API

// Watches a task and raises property-changed notifications when the task completes.
public interface INotifyTaskCompletion : INotifyPropertyChanged
{
  // Gets the task being watched.
  // This property never changes and is never null.
  Task Task { get; }

  // Gets the current task status.
  // This property raises a notification when the task completes.
  TaskStatus Status { get; }

  // Gets whether the task has completed.
  // This property raises a notification when the value changes to true.
  bool IsCompleted { get; }

  // Gets whether the task has completed successfully.
  // This property raises a notification only if the task completes successfully (i.e., if the value changes to true).
  bool IsSuccessfullyCompleted { get; }

  // Gets whether the task has been canceled.
  // This property raises a notification only if the task is canceled (i.e., if the value changes to true).
  bool IsCanceled { get; }

  // Gets whether the task has faulted.
  // This property raises a notification only if the task faults (i.e., if the value changes to true).
  bool IsFaulted { get; }

  // Gets the wrapped faulting exception for the task.
  // Returns null if the task is not faulted.
  // This property raises a notification only if the task faults (i.e., if the value changes to non-null).
  AggregateException Exception { get; }

  // Gets the original faulting exception for the task.
  // Returns null if the task is not faulted.
  // This property raises a notification only if the task faults (i.e., if the value changes to non-null).
  Exception InnerException { get; }

  // Gets the error message for the original faulting exception for the task.
  // Returns null if the task is not faulted.
  // This property raises a notification only if the task faults (i.e., if the value changes to non-null).
  string ErrorMessage { get; }
}

// Watches a task and raises property-changed notifications when the task completes.
public interface INotifyTaskCompletion<TResult> : INotifyTaskCompletion
{
  // Gets the task being watched.
  // This property never changes and is never <c>null</c>.
  new Task<TResult> Task { get; }

  // Gets the result of the task.
  // Returns the default value of <typeparamref name="TResult"/> if the task has not completed successfully.
  // This property raises a notification when the task completes successfully.
  TResult Result { get; }
}

// Factory for task completion notifiers.
public static class NotifyTaskCompletion
{
  // Creates a new task notifier watching the specified task.
  public static INotifyTaskCompletion Create(Task task);

  // Creates a new task notifier watching the specified task.
  public static INotifyTaskCompletion<TResult> Create<TResult>(Task<TResult> task);
}

Platform Support

The full API is supported on all platforms.