TaskExtensions.Unwrap TaskExtensions.Unwrap TaskExtensions.Unwrap TaskExtensions.Unwrap Method

Definición

Sobrecargas

Unwrap(Task<Task>) Unwrap(Task<Task>) Unwrap(Task<Task>)

Crea un proxy Task que representa el funcionamiento asincrónico de TryExecuteTaskInline(Task, Boolean).Creates a proxy Task that represents the asynchronous operation of a TryExecuteTaskInline(Task, Boolean).

Unwrap<TResult>(Task<Task<TResult>>) Unwrap<TResult>(Task<Task<TResult>>) Unwrap<TResult>(Task<Task<TResult>>) Unwrap<TResult>(Task<Task<TResult>>)

Crea una Task de proxy que representa la operación asincrónica de Task<Task<T>> (C#) o Task (Of Task(Of T)) (Visual Basic).Creates a proxy Task that represents the asynchronous operation of a Task<Task<T>> (C#) or Task (Of Task(Of T)) (Visual Basic).

Unwrap(Task<Task>) Unwrap(Task<Task>) Unwrap(Task<Task>)

Crea un proxy Task que representa el funcionamiento asincrónico de TryExecuteTaskInline(Task, Boolean).Creates a proxy Task that represents the asynchronous operation of a TryExecuteTaskInline(Task, Boolean).

public:
[System::Runtime::CompilerServices::Extension]
 static System::Threading::Tasks::Task ^ Unwrap(System::Threading::Tasks::Task<System::Threading::Tasks::Task ^> ^ task);
public static System.Threading.Tasks.Task Unwrap (this System.Threading.Tasks.Task<System.Threading.Tasks.Task> task);
static member Unwrap : System.Threading.Tasks.Task<System.Threading.Tasks.Task> -> System.Threading.Tasks.Task

Parámetros

task
Task<Task>

Task<Task> (C#) o Task (Of Task) (Visual Basic) que se va a desempaquetar.The Task<Task> (C#) or Task (Of Task) (Visual Basic) to unwrap.

Devoluciones

Tarea que representa la operación asincrónica del objeto System.Threading.Tasks.Task(Of Task) proporcionado.A Task that represents the asynchronous operation of the provided System.Threading.Tasks.Task(Of Task).

Excepciones

La excepción que se produce si el argumento task es NULL.The exception that is thrown if the task argument is null.

Ejemplos

El ejemplo siguiente muestra cómo desencapsular una tarea:The following example shows how to unwrap a task:

using System;
using System.Diagnostics;
using System.Threading;
using System.Threading.Tasks;

class UnWrapDemo
{
     // Demonstrated features:
        //		Task.Unwrap()
        // 		Task.Factory.StartNew()
        //		Task.ContinueWith()
        // Expected results:
        // 		Indicates that continuation chains can be set up virtually instantaneously using Unwrap(), and then left to run on their own.
        //      The results of the RemoteIncrement(0) chain and the RemoteIncrement(4) chain may be intermixed with each other.
        //		The results of the sequence that starts with RemoteIncrement(4) are in strict order.
        // Documentation:
        //		http://msdn.microsoft.com/library/dd781129(VS.100).aspx
        // More information:
        //		http://blogs.msdn.com/pfxteam/archive/2009/11/04/9917581.aspx
        // Other notes:
        //		The combination of Task<T>, ContinueWith() and Unwrap() can be particularly useful for setting up a chain of long-running
        //      tasks where each task uses the results of its predecessor.
        static void Main()
        {
            // Invoking individual tasks is straightforward
            Task<int> t1 = RemoteIncrement(0);
            Console.WriteLine("Started RemoteIncrement(0)");

            // Chain together the results of (simulated) remote operations.
            // The use of Unwrap() instead of .Result below prevents this thread from blocking while setting up this continuation chain.
            Task<int> t2 = RemoteIncrement(4)
                .ContinueWith(t => RemoteIncrement(t.Result))			// RemoteIncrement() returns Task<int> so no unwrapping is needed for the first continuation.
                .Unwrap().ContinueWith(t => RemoteIncrement(t.Result))	// ContinueWith() returns Task<Task<int>>. Therefore unwrapping is needed.
                .Unwrap().ContinueWith(t => RemoteIncrement(t.Result))	// and on it goes...
                .Unwrap();
            Console.WriteLine("Started RemoteIncrement(...(RemoteIncrement(RemoteIncrement(4))...)");

            try
            {
                t1.Wait();
                Console.WriteLine("Finished RemoteIncrement(0)\n");

                t2.Wait();
                Console.WriteLine("Finished RemoteIncrement(...(RemoteIncrement(RemoteIncrement(4))...)");
            }
            catch (AggregateException e)
            {
                Console.WriteLine("A task has thrown the following (unexpected) exception:\n{0}", e);
            }

        }
        // This method represents a remote API.
        static Task<int> RemoteIncrement(int n)
        {
            return Task<int>.Factory.StartNew(
                (obj) =>
                {
                    // Simulate a slow operation
                    Thread.Sleep(1 * 1000);

                    int x = (int)obj;
                    Console.WriteLine("Thread={0}, Next={1}", Thread.CurrentThread.ManagedThreadId, ++x);
                    return x;
                },
                n);
        }
      
}

Imports System.Threading
Imports System.Threading.Tasks

Module UnwrapDemo
    ' Demonstrated features:
    '   Task.Unwrap()
    '    Task.Factory.StartNew()
    '   Task.ContinueWith()
    ' Expected results:
    ' 	Indicates that continuation chains can be set up virtually instantaneously using Unwrap(), and then left to run on their own.
    '   The results of the RemoteIncrement(0) chain and the RemoteIncrement(4) chain may be intermixed with each other.
    '   The results of the sequence that starts with RemoteIncrement(4) are in strict order.
    ' Documentation:
    '   http://msdn.microsoft.com/library/dd781129(VS.100).aspx
    ' More information:
    '   http://blogs.msdn.com/pfxteam/archive/2009/11/04/9917581.aspx
    ' Other notes:
    '   The combination of Task<T>, ContinueWith() and Unwrap() can be particularly useful for setting up a chain of long-running
    '   tasks where each task uses the results of its predecessor.

    Sub Main()
        ' Invoking individual tasks is straightforward
        Dim t1 As Task(Of Integer) = RemoteIncrement(0)
        Console.WriteLine("Started RemoteIncrement(0)")

        ' Chain together the results of (simulated) remote operations.
        ' The use of Unwrap() instead of .Result below prevents this thread from blocking while setting up this continuation chain.
        ' RemoteIncrement() returns Task<int> so no unwrapping is needed for the first continuation.
        ' ContinueWith() here returns Task<Task<int>>. Therefore unwrapping is needed.
        ' and on it goes...
        Dim t2 As Task(Of Integer) = RemoteIncrement(4).ContinueWith(Function(t) RemoteIncrement(t.Result)).Unwrap().ContinueWith(Function(t) RemoteIncrement(t.Result)).Unwrap().ContinueWith(Function(t) RemoteIncrement(t.Result)).Unwrap()
        Console.WriteLine("Started RemoteIncrement(...(RemoteIncrement(RemoteIncrement(4))...)")

        Try
            t1.Wait()
            Console.WriteLine("Finished RemoteIncrement(0)" & vbLf)

            t2.Wait()
            Console.WriteLine("Finished RemoteIncrement(...(RemoteIncrement(RemoteIncrement(4))...)")
        Catch e As AggregateException
            Console.WriteLine("A task has thrown the following (unexpected) exception:" & vbLf & "{0}", e)

        End Try
    End Sub

    ' This method represents a remote API.
    Function RemoteIncrement(ByVal n As Integer) As Task(Of Integer)
        Return Task(Of Integer).Factory.StartNew(Function(obj)
                                                     ' Simulate a slow operation
                                                     Thread.Sleep(1 * 1000)

                                                     Dim x As Integer = CInt(obj)
                                                     Console.WriteLine("Thread={0}, Next={1}", Thread.CurrentThread.ManagedThreadId, System.Threading.Interlocked.Increment(x))
                                                     Return x
                                                 End Function, n)
    End Function


End Module

Comentarios

A menudo resulta útil poder devolver una tarea desde un Task<TResult>, donde la tarea interna representa el trabajo realizado como parte de la exterior Task<TResult>.It is often useful to be able to return a Task from a Task<TResult>, where the inner Task represents work done as part of the outer Task<TResult>. Sin embargo, hacerlo resultaría en un Task<Task> (C#) o Task (Of Task) (Visual Basic), que, si no se trata con cuidado, podría generar un comportamiento inesperado.However, doing so results in a Task<Task> (C#) or Task (Of Task) (Visual Basic), which, if not dealt with carefully, could produce unexpected behavior. Unwrap resuelve este problema mediante la creación de una tarea que representa toda la operación asincrónica de una tarea de este tipo de proxy.Unwrap solves this problem by creating a proxy Task that represents the entire asynchronous operation of such a task.

Consulte también:

Unwrap<TResult>(Task<Task<TResult>>) Unwrap<TResult>(Task<Task<TResult>>) Unwrap<TResult>(Task<Task<TResult>>) Unwrap<TResult>(Task<Task<TResult>>)

Crea una Task de proxy que representa la operación asincrónica de Task<Task<T>> (C#) o Task (Of Task(Of T)) (Visual Basic).Creates a proxy Task that represents the asynchronous operation of a Task<Task<T>> (C#) or Task (Of Task(Of T)) (Visual Basic).

public:
generic <typename TResult>
[System::Runtime::CompilerServices::Extension]
 static System::Threading::Tasks::Task<TResult> ^ Unwrap(System::Threading::Tasks::Task<System::Threading::Tasks::Task<TResult> ^> ^ task);
public static System.Threading.Tasks.Task<TResult> Unwrap<TResult> (this System.Threading.Tasks.Task<System.Threading.Tasks.Task<TResult>> task);
static member Unwrap : System.Threading.Tasks.Task<System.Threading.Tasks.Task<'Result>> -> System.Threading.Tasks.Task<'Result>
<Extension()>
Public Function Unwrap(Of TResult) (task As Task(Of Task(Of TResult))) As Task(Of TResult)

Parámetros de tipo

TResult

Tipo del resultado de la tarea.The type of the task's result.

Parámetros

task
Task<Task<TResult>>

Task<Task<T>> (C#) o Task (Of Task(Of T)) (Visual Basic) que se va a desempaquetar.The Task<Task<T>> (C#) or Task (Of Task(Of T)) (Visual Basic) to unwrap.

Devoluciones

Task que representa la operación asincrónica del Task<Task<T>> (C#) o Task (Of Task(Of T)) (Visual Basic) proporcionado.A Task that represents the asynchronous operation of the provided Task<Task<T>> (C#) or Task (Of Task(Of T)) (Visual Basic).

Excepciones

La excepción que se produce si el argumento task es NULL.The exception that is thrown if the task argument is null.

Comentarios

A menudo resulta útil poder devolver un Task desde un Task, donde interno Task representa el trabajo realizado como parte de la exterior Task.It is often useful to be able to return a Task from a Task, where the inner Task represents work done as part of the outer Task. Sin embargo, hacerlo resultaría en un Task<Task<T>> (C#) o Task (Of Task(Of T)) (Visual Basic), que, si no se trata con cuidado, podría generar un comportamiento inesperado.However, doing so results in a Task<Task<T>> (C#) or Task (Of Task(Of T)) (Visual Basic), which, if not dealt with carefully, could produce unexpected behavior. Unwrap resuelve este problema mediante la creación de un proxy Task<TResult> que representa toda la operación asincrónica de tales un Task<Task<T>> (C#) o Task (Of Task(Of T)) (Visual Basic).Unwrap solves this problem by creating a proxy Task<TResult> that represents the entire asynchronous operation of such a Task<Task<T>> (C#) or Task (Of Task(Of T)) (Visual Basic).

Consulte también:

Se aplica a