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ParallelLoopState.Stop Método

Definición

Comunica que el bucle Parallel debe cesar la ejecución en cuanto pueda el sistema.

public:
 void Stop();
public void Stop ();
member this.Stop : unit -> unit
Public Sub Stop ()

Excepciones

Se ha llamado anteriormente al método Break(). Las iteraciones del mismo bucle no pueden utilizar Break() y Stop() en combinación.

Ejemplos

En el ejemplo siguiente se ejecutan hasta 10 000 iteraciones de un bucle en paralelo. Cada iteración se pausa para un intervalo aleatorio de 1 a 1000 milisegundos. Un valor generado aleatoriamente determina en qué iteración del bucle se llama al Stop método. Como se muestra en la salida del ejemplo, no se ejecuta ninguna iteración después de la llamada al Stop método .

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

public class Example
{
   public static void Main()
   {
      var rnd = new Random();
      long stopIndex = rnd.Next(1, 11);

      Console.WriteLine("Will call Stop in iteration {0}\n", stopIndex);

      var result = Parallel.For(1, 10000, (i, state) => {
                                            Console.WriteLine("Beginning iteration {0}", i);
                                            int delay;
                                            Monitor.Enter(rnd);
                                               delay = rnd.Next(1, 1001);
                                            Monitor.Exit(rnd);
                                            Thread.Sleep(delay);
                                            
                                            if (i == stopIndex) {
                                               Console.WriteLine("Stop in iteration {0}", i);
                                               state.Stop();
                                               return;
                                            }

                                            if (state.IsStopped) {
                                               return;
                                            }

                                            Console.WriteLine("Completed iteration {0}", i);
                                       });
   }
}
// The example displays output like the following:
//       Will call Stop in iteration 5
//
//       Beginning iteration 1
//       Beginning iteration 9993
//       Beginning iteration 8744
//       Beginning iteration 6246
//       Beginning iteration 7495
//       Beginning iteration 3748
//       Beginning iteration 4997
//       Beginning iteration 2499
//       Beginning iteration 1250
//       Completed iteration 6246
//       Beginning iteration 6247
//       Completed iteration 3748
//       Beginning iteration 3749
//       Completed iteration 8744
//       Beginning iteration 8745
//       Completed iteration 7495
//       Beginning iteration 7496
//       Completed iteration 1250
//       Beginning iteration 1251
//       Completed iteration 2499
//       Beginning iteration 2500
//       Completed iteration 1
//       Beginning iteration 2
//       Completed iteration 2500
//       Beginning iteration 2501
//       Completed iteration 3749
//       Beginning iteration 3750
//       Completed iteration 6247
//       Beginning iteration 6248
//       Completed iteration 7496
//       Beginning iteration 7497
//       Completed iteration 3750
//       Beginning iteration 3751
//       Completed iteration 2
//       Beginning iteration 3
//       Completed iteration 9993
//       Beginning iteration 9994
//       Completed iteration 8745
//       Beginning iteration 8746
//       Completed iteration 4997
//       Completed iteration 9994
//       Beginning iteration 9995
//       Beginning iteration 4998
//       Completed iteration 6248
//       Beginning iteration 6249
//       Completed iteration 7497
//       Beginning iteration 7498
//       Completed iteration 1251
//       Beginning iteration 1252
//       Completed iteration 2501
//       Beginning iteration 2502
//       Completed iteration 9995
//       Beginning iteration 9996
//       Completed iteration 4998
//       Beginning iteration 4999
//       Completed iteration 2502
//       Beginning iteration 2503
//       Completed iteration 1252
//       Beginning iteration 1253
//       Completed iteration 7498
//       Beginning iteration 7499
//       Completed iteration 3751
//       Beginning iteration 3752
//       Completed iteration 9996
//       Beginning iteration 9997
//       Completed iteration 1253
//       Beginning iteration 1254
//       Completed iteration 9997
//       Beginning iteration 9998
//       Completed iteration 1254
//       Beginning iteration 1255
//       Completed iteration 6249
//       Beginning iteration 6250
//       Completed iteration 3
//       Beginning iteration 4
//       Completed iteration 4
//       Beginning iteration 5
//       Completed iteration 4999
//       Beginning iteration 5000
//       Completed iteration 8746
//       Beginning iteration 8747
//       Stop in iteration 5
Imports System.Threading
Imports System.Threading.Tasks

Module Example
   Public Sub Main()
      Dim rnd As New Random()
      Dim stopIndex As Long = rnd.Next(1, 11)

      Console.WriteLine("Will call Stop in iteration {0}", stopIndex)
      Console.WriteLine()

      Dim result = Parallel.For(1, 10000, Sub(i, state)
                                            Console.WriteLine("Beginning iteration {0}", i)
                                            Dim delay As Integer
                                            Monitor.Enter(rnd)
                                               delay = rnd.Next(1, 1001)
                                            Monitor.Exit(rnd)
                                            Thread.Sleep(delay)

                                            If i = stopIndex Then
                                               Console.WriteLine("Stop in iteration {0}", i)
                                               state.Stop()
                                               Return
                                            End If

                                            If state.IsStopped Then
                                               Return
                                            End If

                                            Console.WriteLine("Completed iteration {0}", i)
                                       End Sub)
    End Sub
End Module
' The example displays output like the following:
'       Will call Stop in iteration 5
'
'       Beginning iteration 1
'       Beginning iteration 9993
'       Beginning iteration 8744
'       Beginning iteration 6246
'       Beginning iteration 7495
'       Beginning iteration 3748
'       Beginning iteration 4997
'       Beginning iteration 2499
'       Beginning iteration 1250
'       Completed iteration 6246
'       Beginning iteration 6247
'       Completed iteration 3748
'       Beginning iteration 3749
'       Completed iteration 8744
'       Beginning iteration 8745
'       Completed iteration 7495
'       Beginning iteration 7496
'       Completed iteration 1250
'       Beginning iteration 1251
'       Completed iteration 2499
'       Beginning iteration 2500
'       Completed iteration 1
'       Beginning iteration 2
'       Completed iteration 2500
'       Beginning iteration 2501
'       Completed iteration 3749
'       Beginning iteration 3750
'       Completed iteration 6247
'       Beginning iteration 6248
'       Completed iteration 7496
'       Beginning iteration 7497
'       Completed iteration 3750
'       Beginning iteration 3751
'       Completed iteration 2
'       Beginning iteration 3
'       Completed iteration 9993
'       Beginning iteration 9994
'       Completed iteration 8745
'       Beginning iteration 8746
'       Completed iteration 4997
'       Completed iteration 9994
'       Beginning iteration 9995
'       Beginning iteration 4998
'       Completed iteration 6248
'       Beginning iteration 6249
'       Completed iteration 7497
'       Beginning iteration 7498
'       Completed iteration 1251
'       Beginning iteration 1252
'       Completed iteration 2501
'       Beginning iteration 2502
'       Completed iteration 9995
'       Beginning iteration 9996
'       Completed iteration 4998
'       Beginning iteration 4999
'       Completed iteration 2502
'       Beginning iteration 2503
'       Completed iteration 1252
'       Beginning iteration 1253
'       Completed iteration 7498
'       Beginning iteration 7499
'       Completed iteration 3751
'       Beginning iteration 3752
'       Completed iteration 9996
'       Beginning iteration 9997
'       Completed iteration 1253
'       Beginning iteration 1254
'       Completed iteration 9997
'       Beginning iteration 9998
'       Completed iteration 1254
'       Beginning iteration 1255
'       Completed iteration 6249
'       Beginning iteration 6250
'       Completed iteration 3
'       Beginning iteration 4
'       Completed iteration 4
'       Beginning iteration 5
'       Completed iteration 4999
'       Beginning iteration 5000
'       Completed iteration 8746
'       Beginning iteration 8747
'       Stop in iteration 5

Dado que es probable que las iteraciones del bucle se ejecuten cuando se llama al Stop método , cada iteración llama al IsStopped método para comprobar si otra iteración ha llamado al Stop método . Si devuelve true, la iteración devuelve inmediatamente.

Comentarios

Llamar al Stop método indica que no es necesario ejecutar las iteraciones del bucle que aún no se han iniciado. Cancela eficazmente las iteraciones adicionales del bucle. Sin embargo, no detiene las iteraciones que ya han comenzado a ejecutarse.

Al llamar al Stop método , la IsStopped propiedad se devuelve true para cualquier iteración del bucle que todavía se está ejecutando. Esto es especialmente útil para iteraciones de larga duración, que pueden comprobar la IsStopped propiedad y salir pronto si su valor es true.

Stop normalmente se emplea en algoritmos basados en búsquedas, donde una vez que se encuentra un resultado, no es necesario ejecutar otras iteraciones.

Se aplica a

Consulte también