Task<TResult>.Factory Property

Definition

Fornisce l'accesso ai metodi factory per la creazione e la configurazione delle istanze di 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)

Property Value

TaskFactory<TResult>

Oggetto factory in grado di creare una vasta gamma di oggetti Task<TResult>.A factory object that can create a variety of Task<TResult> objects.

Remarks

Questa proprietà restituisce un'istanza predefinita della classe TaskFactory<TResult> identica a quella creata chiamando il costruttore di TaskFactory<TResult>.TaskFactory<TResult>() senza parametri.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. Dispone dei valori di proprietà seguenti:It has the following property values:

ProprietàProperty valoreValue
TaskFactory<TResult>.CancellationToken CancellationToken.None
TaskFactory<TResult>.ContinuationOptions TaskContinuationOptions.None
TaskFactory<TResult>.CreationOptions TaskCreationOptions.None
TaskFactory<TResult>.Scheduler null o TaskScheduler.Currentnull, or TaskScheduler.Current

L'uso più comune di questa proprietà consiste nel creare e avviare una nuova attività in una singola chiamata al metodo TaskFactory<TResult>.StartNew.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.

Note

A partire dalla .NET Framework 4.5.NET Framework 4.5, il metodo Task.Run fornisce il modo più semplice per creare un oggetto Task<TResult> con i valori di configurazione predefiniti.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.

Nell'esempio seguente viene utilizzata la proprietà Factory statica per effettuare tre chiamate al metodo TaskFactory<TResult>.StartNew.The following example uses the static Factory property to make three calls to the TaskFactory<TResult>.StartNew method. Il primo avvia un oggetto Task<Int32>, che esegue un'espressione lambda che restituisce 1.The first starts a Task<Int32> object, which executes a lambda expression that returns 1. Il secondo avvia un oggetto Task<Test>, che esegue un'espressione lambda che crea un'istanza di una nuova istanza di Test.The second starts a Task<Test> object, which executes a lambda expression that instantiates a new Test instance. Il terzo avvia un oggetto Task<String[]>, che enumera i file nella directory C:\Users\Public\Pictures\Sample Pictures .The third starts a Task<String[]> object, which enumerates the files in the C:\Users\Public\Pictures\Sample Pictures\ directory. Si noti che l'esecuzione corretta dell'esempio richiede che la directory esista e che contenga i file.(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

Applies to

See also