Task<TResult>.Factory Propriété

Définition

Fournit l’accès aux méthodes de fabrique pour la création et la configuration d’instances de Task<TResult>.Provides access to factory methods for creating and configuring Task<TResult> instances.

public:
 static property System::Threading::Tasks::TaskFactory<TResult> ^ Factory { System::Threading::Tasks::TaskFactory<TResult> ^ get(); };
public static System.Threading.Tasks.TaskFactory<TResult> Factory { get; }
member this.Factory : System.Threading.Tasks.TaskFactory<'Result>
Public Shared ReadOnly Property Factory As TaskFactory(Of TResult)

Valeur de propriété

TaskFactory<TResult>

Objet de fabrique pouvant créer une variété d'objets Task<TResult>.A factory object that can create a variety of Task<TResult> objects.

Remarques

Cette propriété retourne une instance par défaut de la TaskFactory<TResult> classe qui est identique à celle créée en appelant le constructeur sans paramètre TaskFactory<TResult>.TaskFactory<TResult>() .This property returns a default instance of the TaskFactory<TResult> class that is identical to the one created by calling the parameterless TaskFactory<TResult>.TaskFactory<TResult>() constructor. Il a les valeurs de propriétés suivantes :It has the following property values:

PropriétéProperty ValeurValue
TaskFactory<TResult>.CancellationToken CancellationToken.None
TaskFactory<TResult>.ContinuationOptions TaskContinuationOptions.None
TaskFactory<TResult>.CreationOptions TaskCreationOptions.None
TaskFactory<TResult>.Scheduler null ou TaskScheduler.Currentnull, or TaskScheduler.Current

L’utilisation la plus courante de cette propriété est la création et le démarrage d’une nouvelle tâche dans un appel unique à la TaskFactory<TResult>.StartNew méthode.The most common use of this property is to create and start a new task in a single call to the TaskFactory<TResult>.StartNew method.

Notes

À compter de .NET Framework 4.5.NET Framework 4.5 , la Task.Run méthode offre le moyen le plus simple de créer un Task<TResult> objet avec les valeurs de configuration par défaut.Starting with the .NET Framework 4.5.NET Framework 4.5, the Task.Run method provides the easiest way to create a Task<TResult> object with default configuration values.

L’exemple suivant utilise la Factory propriété statique pour effectuer trois appels à la TaskFactory<TResult>.StartNew méthode.The following example uses the static Factory property to make three calls to the TaskFactory<TResult>.StartNew method. La première démarre un Task<Int32> objet, qui exécute une expression lambda qui retourne 1.The first starts a Task<Int32> object, which executes a lambda expression that returns 1. Le deuxième démarre un Task<Test> objet, qui exécute une expression lambda qui instancie une nouvelle Test instance.The second starts a Task<Test> object, which executes a lambda expression that instantiates a new Test instance. Le troisième démarre un Task<String[]> objet, qui énumère les fichiers dans le répertoire C:\Users\Public\Pictures\Sample images .The third starts a Task<String[]> object, which enumerates the files in the C:\Users\Public\Pictures\Sample Pictures\ directory. (Notez que l’exécution réussie de l’exemple requiert que le répertoire existe et qu’il contienne des fichiers.(Note that successful execution of the example requires that the directory exist and that it contain files.

using System;
using System.Linq;
using System.Threading.Tasks;

class Program
{
    static void Main()
    {
        // Return a value type with a lambda expression
        Task<int> task1 = Task<int>.Factory.StartNew(() => 1);
        int i = task1.Result;

        // Return a named reference type with a multi-line statement lambda.
        Task<Test> task2 = Task<Test>.Factory.StartNew(() =>
        {
            string s = ".NET";
            double d = 4.0;
            return new Test { Name = s, Number = d };
        });
        Test test = task2.Result;

        // Return an array produced by a PLINQ query
        Task<string[]> task3 = Task<string[]>.Factory.StartNew(() =>
        {
            string path = @"C:\Users\Public\Pictures\Sample Pictures\";
            string[] files = System.IO.Directory.GetFiles(path);

            var result = (from file in files.AsParallel()
                          let info = new System.IO.FileInfo(file)
                          where info.Extension == ".jpg"
                          select file).ToArray();

            return result;
        });

        foreach (var name in task3.Result)
            Console.WriteLine(name);
    }
    class Test
    {
        public string Name { get; set; }
        public double Number { get; set; }
    }
}
Imports System.Threading.Tasks

Module Module1

    Sub Main()
        ReturnAValue()

        Console.WriteLine("Press any key to exit.")
        Console.ReadKey()

    End Sub

    Sub ReturnAValue()

        ' Return a value type with a lambda expression
        Dim task1 = Task(Of Integer).Factory.StartNew(Function() 1)
        Dim i As Integer = task1.Result

        ' Return a named reference type with a multi-line statement lambda.
        Dim task2 As Task(Of Test) = Task.Factory.StartNew(Function()
                                                               Dim s As String = ".NET"
                                                               Dim d As Integer = 4
                                                               Return New Test With {.Name = s, .Number = d}
                                                           End Function)

        Dim myTest As Test = task2.Result
        Console.WriteLine(myTest.Name & ": " & myTest.Number)

        ' Return an array produced by a PLINQ query.
        Dim task3 As Task(Of String())= Task(Of String()).Factory.StartNew(Function()

                                                           Dim path = "C:\Users\Public\Pictures\Sample Pictures\"
                                                           Dim files = System.IO.Directory.GetFiles(path)

                                                           Dim result = (From file In files.AsParallel()
                                                                Let info = New System.IO.FileInfo(file)
                                                                Where info.Extension = ".jpg"
                                                                Select file).ToArray()
                                                           Return result
                                                       End Function)

        For Each name As String In task3.Result
            Console.WriteLine(name)
        Next
    End Sub

    Class Test
        Public Name As String
        Public Number As Double
    End Class
End Module

S’applique à

Voir aussi