Thread.IsBackground Thread.IsBackground Thread.IsBackground Thread.IsBackground Property

Definición

Obtiene o establece un valor que indica si un subproceso es o no un subproceso en segundo plano.Gets or sets a value indicating whether or not a thread is a background thread.

public:
 property bool IsBackground { bool get(); void set(bool value); };
public bool IsBackground { get; set; }
member this.IsBackground : bool with get, set
Public Property IsBackground As Boolean

Valor de propiedad

true si el subproceso es un subproceso en segundo plano o va a convertirse en un subproceso en segundo plano; en caso contrario, false.true if this thread is or is to become a background thread; otherwise, false.

Excepciones

Ejemplos

En el ejemplo siguiente se compara el comportamiento de los subprocesos de primer plano y en segundo plano.The following example contrasts the behavior of foreground and background threads. Crea un subproceso en primer plano y un subproceso en segundo plano.It creates a foreground thread and a background thread. El subproceso en primer plano mantiene el proceso en ejecución for hasta que complete su bucle y termine.The foreground thread keeps the process running until completes its for loop and terminates. Sin embargo, como muestra el resultado del ejemplo, dado que el subproceso en primer plano ha finalizado la ejecución, el proceso finaliza antes de que el subproceso en segundo plano haya finalizado la ejecución.However, as the output from the example shows, because the foreground thread has finished execution, the process is terminated before the background thread has completed execution.

using namespace System;
using namespace System::Threading;

ref class BackgroundTest
{
private:
   int maxIterations;

public:
   BackgroundTest(int maxIterations)
   {
      this->maxIterations = maxIterations;
   }

   void RunLoop()
   {
      for (int i = 0; i < maxIterations; i++ )
      {
         Console::WriteLine("{0} count: {1}", 
              Thread::CurrentThread->IsBackground ? 
              "Background Thread" : "Foreground Thread", i);
         Thread::Sleep(250);

      }
      Console::WriteLine("{0} finished counting.", 
                         Thread::CurrentThread->IsBackground ? 
                         "Background Thread" : "Foreground Thread");
   }
};

int main()
{
   BackgroundTest^ shortTest = gcnew BackgroundTest( 10 );
   Thread^ foregroundThread = gcnew Thread( gcnew ThreadStart( shortTest, &BackgroundTest::RunLoop ) );
   foregroundThread->Name =  "ForegroundThread";
   BackgroundTest^ longTest = gcnew BackgroundTest( 50 );
   Thread^ backgroundThread = gcnew Thread( gcnew ThreadStart( longTest, &BackgroundTest::RunLoop ) );
   backgroundThread->Name =  "BackgroundThread";
   backgroundThread->IsBackground = true;
   foregroundThread->Start();
   backgroundThread->Start();
}

using System;
using System.Threading;

class Example
{
    static void Main()
    {
        BackgroundTest shortTest = new BackgroundTest(10);
        Thread foregroundThread = 
            new Thread(new ThreadStart(shortTest.RunLoop));

        BackgroundTest longTest = new BackgroundTest(50);
        Thread backgroundThread = 
            new Thread(new ThreadStart(longTest.RunLoop));
        backgroundThread.IsBackground = true;

        foregroundThread.Start();
        backgroundThread.Start();
    }
}

class BackgroundTest
{
    int maxIterations;

    public BackgroundTest(int maxIterations)
    {
        this.maxIterations = maxIterations;
    }

    public void RunLoop()
    {
        for (int i = 0; i < maxIterations; i++) {
            Console.WriteLine("{0} count: {1}", 
                Thread.CurrentThread.IsBackground ? 
                   "Background Thread" : "Foreground Thread", i);
            Thread.Sleep(250);
        }
        Console.WriteLine("{0} finished counting.", 
                          Thread.CurrentThread.IsBackground ? 
                          "Background Thread" : "Foreground Thread");
    }
}
// The example displays output like the following:
//    Foreground Thread count: 0
//    Background Thread count: 0
//    Background Thread count: 1
//    Foreground Thread count: 1
//    Foreground Thread count: 2
//    Background Thread count: 2
//    Foreground Thread count: 3
//    Background Thread count: 3
//    Background Thread count: 4
//    Foreground Thread count: 4
//    Foreground Thread count: 5
//    Background Thread count: 5
//    Foreground Thread count: 6
//    Background Thread count: 6
//    Background Thread count: 7
//    Foreground Thread count: 7
//    Background Thread count: 8
//    Foreground Thread count: 8
//    Foreground Thread count: 9
//    Background Thread count: 9
//    Background Thread count: 10
//    Foreground Thread count: 10
//    Background Thread count: 11
//    Foreground Thread finished counting.
Imports System.Threading

Public Module Example
    Public Sub Main()
        Dim shortTest As New BackgroundTest(10)
        Dim foregroundThread As New Thread(AddressOf shortTest.RunLoop)

        Dim longTest As New BackgroundTest(50)
        Dim backgroundThread As New Thread(AddressOf longTest.RunLoop)
        backgroundThread.IsBackground = True

        foregroundThread.Start()
        backgroundThread.Start()
    End Sub
End Module

Public Class BackgroundTest
    Dim maxIterations As Integer 

    Sub New(maximumIterations As Integer)
        maxIterations = maximumIterations
    End Sub

    Sub RunLoop()
        For i As Integer = 0 To maxIterations
            Console.WriteLine("{0} count: {1}", _
                    If(Thread.CurrentThread.IsBackground, 
                       "Background Thread", "Foreground Thread"), i)
            Thread.Sleep(250)
        Next 

        Console.WriteLine("{0} finished counting.", 
                          If(Thread.CurrentThread.IsBackground, 
                          "Background Thread", "Foreground Thread"))
    End Sub
End Class
' The example displays output like the following:
'    Foreground Thread count: 0
'    Background Thread count: 0
'    Background Thread count: 1
'    Foreground Thread count: 1
'    Foreground Thread count: 2
'    Background Thread count: 2
'    Foreground Thread count: 3
'    Background Thread count: 3
'    Background Thread count: 4
'    Foreground Thread count: 4
'    Foreground Thread count: 5
'    Background Thread count: 5
'    Foreground Thread count: 6
'    Background Thread count: 6
'    Background Thread count: 7
'    Foreground Thread count: 7
'    Background Thread count: 8
'    Foreground Thread count: 8
'    Foreground Thread count: 9
'    Background Thread count: 9
'    Background Thread count: 10
'    Foreground Thread count: 10
'    Background Thread count: 11
'    Foreground Thread finished counting.

Comentarios

Un subproceso es un subproceso en segundo plano o un subproceso en primer plano.A thread is either a background thread or a foreground thread. Los subprocesos en segundo plano son idénticos a los subprocesos de primer plano, excepto en que los subprocesos en segundo plano no impiden queBackground threads are identical to foreground threads, except that background threads do not prevent a process from terminating. Una vez finalizados todos los subprocesos en primer plano que pertenecen a un proceso, el Common Language Runtime finaliza el proceso.Once all foreground threads belonging to a process have terminated, the common language runtime ends the process. Los subprocesos en segundo plano restantes se detienen y no se completan.Any remaining background threads are stopped and do not complete.

De forma predeterminada, los subprocesos siguientes se ejecutan en primer plano IsBackground (es falsedecir, la propiedad devuelve):By default, the following threads execute in the foreground (that is, their IsBackground property returns false):

  • El subproceso principal (o el subproceso de aplicación principal).The primary thread (or main application thread).

  • Todos los subprocesos creados Thread mediante una llamada a un constructor de clase.All threads created by calling a Thread class constructor.

De forma predeterminada, los subprocesos siguientes se ejecutan en segundo plano IsBackground (es truedecir, la propiedad devuelve):By default, the following threads execute in the background (that is, their IsBackground property returns true):

  • Subprocesos del grupo de subprocesos, que son un grupo de subprocesos de trabajo mantenido por el tiempo de ejecución.Thread pool threads, which are a pool of worker threads maintained by the runtime. Puede configurar el grupo de subprocesos y programar el trabajo en subprocesos ThreadPool del grupo de subprocesos mediante la clase.You can configure the thread pool and schedule work on thread pool threads by using the ThreadPool class.

    Nota

    Las operaciones asincrónicas basadas en tareas se ejecutan automáticamente en subprocesos del grupo de subprocesos.Task-based asynchronous operations automatically execute on thread pool threads.

  • Todos los subprocesos que entran en el entorno de ejecución administrado desde código no administrado.All threads that enter the managed execution environment from unmanaged code.

Se aplica a

Consulte también: