Parallel.For Parallel.For Parallel.For Parallel.For Method

Definição

Executa um loop for (For no Visual Basic) no qual as iterações podem ser executadas em paralelo.Executes a for (For in Visual Basic) loop in which iterations may run in parallel.

Sobrecargas

For(Int32, Int32, Action<Int32,ParallelLoopState>) For(Int32, Int32, Action<Int32,ParallelLoopState>) For(Int32, Int32, Action<Int32,ParallelLoopState>) For(Int32, Int32, Action<Int32,ParallelLoopState>)

Executa um loop for (For no Visual Basic) no qual as iterações podem ser executadas em paralelo e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop in which iterations may run in parallel and the state of the loop can be monitored and manipulated.

For(Int32, Int32, Action<Int32>) For(Int32, Int32, Action<Int32>) For(Int32, Int32, Action<Int32>) For(Int32, Int32, Action<Int32>)

Executa um loop for (For no Visual Basic) no qual as iterações podem ser executadas em paralelo.Executes a for (For in Visual Basic) loop in which iterations may run in parallel.

For(Int64, Int64, Action<Int64,ParallelLoopState>) For(Int64, Int64, Action<Int64,ParallelLoopState>) For(Int64, Int64, Action<Int64,ParallelLoopState>) For(Int64, Int64, Action<Int64,ParallelLoopState>)

Executa um loop for (For no Visual Basic) com índices de 64 bits no qual as iterações podem ser executadas em paralelo e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop with 64-bit indexes in which iterations may run in parallel and the state of the loop can be monitored and manipulated.

For(Int64, Int64, Action<Int64>) For(Int64, Int64, Action<Int64>) For(Int64, Int64, Action<Int64>) For(Int64, Int64, Action<Int64>)

Executa um loop for (For no Visual Basic) com índices de 64 bits no qual as iterações podem ser executadas em paralelo.Executes a for (For in Visual Basic) loop with 64-bit indexes in which iterations may run in parallel.

For(Int32, Int32, ParallelOptions, Action<Int32,ParallelLoopState>) For(Int32, Int32, ParallelOptions, Action<Int32,ParallelLoopState>) For(Int32, Int32, ParallelOptions, Action<Int32,ParallelLoopState>)

Executa um loop for (For no Visual Basic) no qual as iterações podem ser executadas em paralelo, as opções do loop podem ser configuradas e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop in which iterations may run in parallel, loop options can be configured, and the state of the loop can be monitored and manipulated.

For(Int32, Int32, ParallelOptions, Action<Int32>) For(Int32, Int32, ParallelOptions, Action<Int32>) For(Int32, Int32, ParallelOptions, Action<Int32>)

Executa um loop for (For no Visual Basic) em que as iterações podem ser executadas em paralelo e as opções de loop podem ser configuradas.Executes a for (For in Visual Basic) loop in which iterations may run in parallel and loop options can be configured.

For(Int64, Int64, ParallelOptions, Action<Int64,ParallelLoopState>) For(Int64, Int64, ParallelOptions, Action<Int64,ParallelLoopState>) For(Int64, Int64, ParallelOptions, Action<Int64,ParallelLoopState>)

Executa um loop for (For no Visual Basic) com índices de 64 bits no qual iterações podem ser executadas em paralelo, opções de loop podem ser configuradas e o estado de loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop with 64-bit indexes in which iterations may run in parallel, loop options can be configured, and the state of the loop can be monitored and manipulated.

For(Int64, Int64, ParallelOptions, Action<Int64>) For(Int64, Int64, ParallelOptions, Action<Int64>) For(Int64, Int64, ParallelOptions, Action<Int64>)

Executa um loop for (For no Visual Basic) com índices de 64 bits no qual as iterações podem ser executadas em paralelo e opções de loop podem ser configuradas.Executes a for (For in Visual Basic) loop with 64-bit indexes in which iterations may run in parallel and loop options can be configured.

For<TLocal>(Int64, Int64, ParallelOptions, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int64, Int64, ParallelOptions, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int64, Int64, ParallelOptions, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>)

Executa um loop for (For no Visual Basic) com índices de 64 bits e dados locais do thread nos quais iterações podem ser executadas em paralelo, opções de loop podem ser configuradas e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop with 64-bit indexes and thread-local data in which iterations may run in parallel, loop options can be configured, and the state of the loop can be monitored and manipulated.

For<TLocal>(Int32, Int32, ParallelOptions, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int32, Int32, ParallelOptions, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int32, Int32, ParallelOptions, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>)

Executa um loop for (For no Visual Basic) com os dados locais do thread nos quais iterações podem ser executadas em paralelo, opções de loop podem ser configuradas e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop with thread-local data in which iterations may run in parallel, loop options can be configured, and the state of the loop can be monitored and manipulated.

For<TLocal>(Int32, Int32, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int32, Int32, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int32, Int32, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int32, Int32, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>)

Executa um loop for (For no Visual Basic) com os dados locais de thread no qual as iterações podem ser executadas em paralelo e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop with thread-local data in which iterations may run in parallel, and the state of the loop can be monitored and manipulated.

For<TLocal>(Int64, Int64, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int64, Int64, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int64, Int64, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int64, Int64, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>)

Executa um loop for (For no Visual Basic) com índices de 64 bits e dados locais de thread no qual as iterações podem ser executadas em paralelo e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop with 64-bit indexes and thread-local data in which iterations may run in parallel, and the state of the loop can be monitored and manipulated.

For(Int32, Int32, Action<Int32,ParallelLoopState>) For(Int32, Int32, Action<Int32,ParallelLoopState>) For(Int32, Int32, Action<Int32,ParallelLoopState>) For(Int32, Int32, Action<Int32,ParallelLoopState>)

Executa um loop for (For no Visual Basic) no qual as iterações podem ser executadas em paralelo e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop in which iterations may run in parallel and the state of the loop can be monitored and manipulated.

public:
 static System::Threading::Tasks::ParallelLoopResult For(int fromInclusive, int toExclusive, Action<int, System::Threading::Tasks::ParallelLoopState ^> ^ body);
public static System.Threading.Tasks.ParallelLoopResult For (int fromInclusive, int toExclusive, Action<int,System.Threading.Tasks.ParallelLoopState> body);
static member For : int * int * Action<int, System.Threading.Tasks.ParallelLoopState> -> System.Threading.Tasks.ParallelLoopResult
Public Shared Function For (fromInclusive As Integer, toExclusive As Integer, body As Action(Of Integer, ParallelLoopState)) As ParallelLoopResult

Parâmetros

fromInclusive
Int32 Int32 Int32 Int32

O índice inicial, inclusivo.The start index, inclusive.

toExclusive
Int32 Int32 Int32 Int32

O índice final, exclusivo.The end index, exclusive.

body
Action<Int32,ParallelLoopState>

O delegado invocado uma vez por iteração.The delegate that is invoked once per iteration.

Retornos

Uma estrutura que contém informações sobre qual parte do loop foi concluída.A structure that contains information about which portion of the loop completed.

Exceções

O argumento body é null.The body argument is null.

A exceção que contém todas as exceções individuais lançadas em todos os threads.The exception that contains all the individual exceptions thrown on all threads.

Exemplos

O exemplo a seguir executa até 100 iterações de um loop em paralelo.The following example executes up to 100 iterations of a loop in parallel. Cada iteração pausa por um intervalo aleatório de 1 a 1.000 milissegundos.Each iteration pauses for a random interval from 1 to 1,000 milliseconds. Um valor gerado aleatoriamente determina em qual iteração do loop de ParallelLoopState.Break método é chamado.A randomly generated value determines on which iteration of the loop the ParallelLoopState.Break method is called. Como a saída do exemplo mostra, nenhuma iteração cujo índice é maior que o ParallelLoopState.LowestBreakIteration início do valor de propriedade após a chamada para o ParallelLoopState.Break método.As the output from the example shows, no iterations whose index is greater than the ParallelLoopState.LowestBreakIteration property value start after the call to the ParallelLoopState.Break method.

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

public class Example
{
   public static void Main()
   {
      var rnd = new Random();
      int breakIndex = rnd.Next(1, 11);
      Nullable<long> lowest = new Nullable<long>();

      Console.WriteLine("Will call Break at iteration {0}\n",
                        breakIndex);

      var result = Parallel.For(1, 101, (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 (state.ShouldExitCurrentIteration) {
                                               if (state.LowestBreakIteration < i)
                                                  return;
                                            }

                                            if (i == breakIndex) {
                                               Console.WriteLine("Break in iteration {0}", i);
                                               state.Break();
                                               if (state.LowestBreakIteration.HasValue)
                                                  if (lowest < state.LowestBreakIteration)
                                                     lowest = state.LowestBreakIteration;
                                                  else
                                                     lowest = state.LowestBreakIteration;
                                            }

                                            Console.WriteLine("Completed iteration {0}", i);
                                       });
         if (lowest.HasValue)
            Console.WriteLine("\nLowest Break Iteration: {0}", lowest);
         else
            Console.WriteLine("\nNo lowest break iteration.");
   }
}
// The example displays output like the following:
//       Will call Break at iteration 8
//
//       Beginning iteration 1
//       Beginning iteration 13
//       Beginning iteration 97
//       Beginning iteration 25
//       Beginning iteration 49
//       Beginning iteration 37
//       Beginning iteration 85
//       Beginning iteration 73
//       Beginning iteration 61
//       Completed iteration 85
//       Beginning iteration 86
//       Completed iteration 61
//       Beginning iteration 62
//       Completed iteration 86
//       Beginning iteration 87
//       Completed iteration 37
//       Beginning iteration 38
//       Completed iteration 38
//       Beginning iteration 39
//       Completed iteration 25
//       Beginning iteration 26
//       Completed iteration 26
//       Beginning iteration 27
//       Completed iteration 73
//       Beginning iteration 74
//       Completed iteration 62
//       Beginning iteration 63
//       Completed iteration 39
//       Beginning iteration 40
//       Completed iteration 40
//       Beginning iteration 41
//       Completed iteration 13
//       Beginning iteration 14
//       Completed iteration 1
//       Beginning iteration 2
//       Completed iteration 97
//       Beginning iteration 98
//       Completed iteration 49
//       Beginning iteration 50
//       Completed iteration 87
//       Completed iteration 27
//       Beginning iteration 28
//       Completed iteration 50
//       Beginning iteration 51
//       Beginning iteration 88
//       Completed iteration 14
//       Beginning iteration 15
//       Completed iteration 15
//       Completed iteration 2
//       Beginning iteration 3
//       Beginning iteration 16
//       Completed iteration 63
//       Beginning iteration 64
//       Completed iteration 74
//       Beginning iteration 75
//       Completed iteration 41
//       Beginning iteration 42
//       Completed iteration 28
//       Beginning iteration 29
//       Completed iteration 29
//       Beginning iteration 30
//       Completed iteration 98
//       Beginning iteration 99
//       Completed iteration 64
//       Beginning iteration 65
//       Completed iteration 42
//       Beginning iteration 43
//       Completed iteration 88
//       Beginning iteration 89
//       Completed iteration 51
//       Beginning iteration 52
//       Completed iteration 16
//       Beginning iteration 17
//       Completed iteration 43
//       Beginning iteration 44
//       Completed iteration 44
//       Beginning iteration 45
//       Completed iteration 99
//       Beginning iteration 4
//       Completed iteration 3
//       Beginning iteration 8
//       Completed iteration 4
//       Beginning iteration 5
//       Completed iteration 52
//       Beginning iteration 53
//       Completed iteration 75
//       Beginning iteration 76
//       Completed iteration 76
//       Beginning iteration 77
//       Completed iteration 65
//       Beginning iteration 66
//       Completed iteration 5
//       Beginning iteration 6
//       Completed iteration 89
//       Beginning iteration 90
//       Completed iteration 30
//       Beginning iteration 31
//       Break in iteration 8
//       Completed iteration 8
//       Completed iteration 6
//       Beginning iteration 7
//       Completed iteration 7
//
//       Lowest Break Iteration: 8
Imports System.Threading
Imports System.Threading.Tasks

Module Example
   Public Sub Main()
      Dim rnd As New Random()
      Dim breakIndex As Integer = rnd.Next(1, 11)
      Dim lowest As New Nullable(Of Long)()

      Console.WriteLine("Will call Break at iteration {0}", breakIndex)
      Console.WriteLine()

      Dim result = Parallel.For(1, 101, 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 state.ShouldExitCurrentIteration Then
                                               If state.LowestBreakIteration < i Then
                                                  Return
                                               End If
                                            End If

                                            If i = breakIndex Then
                                               Console.WriteLine("Break in iteration {0}", i)
                                               state.Break()
                                               If state.LowestBreakIteration.HasValue Then
                                                  If lowest < state.LowestBreakIteration Then
                                                     lowest = state.LowestBreakIteration
                                                  Else
                                                     lowest = state.LowestBreakIteration
                                                  End If
                                               End If
                                            End If

                                            Console.WriteLine("Completed iteration {0}", i)
                                       End Sub )
         Console.WriteLine()
         If lowest.HasValue Then
            Console.WriteLine("Lowest Break Iteration: {0}", lowest)
         Else
            Console.WriteLine("No lowest break iteration.")
         End If
   End Sub
End Module
' The example displays output like the following:
'       Will call Break at iteration 8
'
'       Beginning iteration 1
'       Beginning iteration 13
'       Beginning iteration 97
'       Beginning iteration 25
'       Beginning iteration 49
'       Beginning iteration 37
'       Beginning iteration 85
'       Beginning iteration 73
'       Beginning iteration 61
'       Completed iteration 85
'       Beginning iteration 86
'       Completed iteration 61
'       Beginning iteration 62
'       Completed iteration 86
'       Beginning iteration 87
'       Completed iteration 37
'       Beginning iteration 38
'       Completed iteration 38
'       Beginning iteration 39
'       Completed iteration 25
'       Beginning iteration 26
'       Completed iteration 26
'       Beginning iteration 27
'       Completed iteration 73
'       Beginning iteration 74
'       Completed iteration 62
'       Beginning iteration 63
'       Completed iteration 39
'       Beginning iteration 40
'       Completed iteration 40
'       Beginning iteration 41
'       Completed iteration 13
'       Beginning iteration 14
'       Completed iteration 1
'       Beginning iteration 2
'       Completed iteration 97
'       Beginning iteration 98
'       Completed iteration 49
'       Beginning iteration 50
'       Completed iteration 87
'       Completed iteration 27
'       Beginning iteration 28
'       Completed iteration 50
'       Beginning iteration 51
'       Beginning iteration 88
'       Completed iteration 14
'       Beginning iteration 15
'       Completed iteration 15
'       Completed iteration 2
'       Beginning iteration 3
'       Beginning iteration 16
'       Completed iteration 63
'       Beginning iteration 64
'       Completed iteration 74
'       Beginning iteration 75
'       Completed iteration 41
'       Beginning iteration 42
'       Completed iteration 28
'       Beginning iteration 29
'       Completed iteration 29
'       Beginning iteration 30
'       Completed iteration 98
'       Beginning iteration 99
'       Completed iteration 64
'       Beginning iteration 65
'       Completed iteration 42
'       Beginning iteration 43
'       Completed iteration 88
'       Beginning iteration 89
'       Completed iteration 51
'       Beginning iteration 52
'       Completed iteration 16
'       Beginning iteration 17
'       Completed iteration 43
'       Beginning iteration 44
'       Completed iteration 44
'       Beginning iteration 45
'       Completed iteration 99
'       Beginning iteration 4
'       Completed iteration 3
'       Beginning iteration 8
'       Completed iteration 4
'       Beginning iteration 5
'       Completed iteration 52
'       Beginning iteration 53
'       Completed iteration 75
'       Beginning iteration 76
'       Completed iteration 76
'       Beginning iteration 77
'       Completed iteration 65
'       Beginning iteration 66
'       Completed iteration 5
'       Beginning iteration 6
'       Completed iteration 89
'       Beginning iteration 90
'       Completed iteration 30
'       Beginning iteration 31
'       Break in iteration 8
'       Completed iteration 8
'       Completed iteration 6
'       Beginning iteration 7
'       Completed iteration 7
'
'       Lowest Break Iteration: 8

Como as iterações do loop são ainda podem estar em execução quando o ParallelLoopState.Break método é chamado, as chamadas de cada iteração a ParallelLoopState.ShouldExitCurrentIteration propriedade para verificar se a outra iteração tiver chamado o ParallelLoopState.Break método.Because iterations of the loop are still likely to be executing when the ParallelLoopState.Break method is called, each iteration calls the ParallelLoopState.ShouldExitCurrentIteration property to check whether another iteration has called the ParallelLoopState.Break method. Se o valor da propriedade for true, a iteração verifica o valor da ParallelLoopState.LowestBreakIteration propriedade e, se ele for maior que o valor de índice da iteração atual, retorna imediatamente.If the property value is true, the iteration checks the value of the ParallelLoopState.LowestBreakIteration property and, if it is greater than the current iteration's index value, returns immediately.

Comentários

O body delegado é invocado uma vez para cada valor no intervalo de iteração (fromInclusive, toExclusive).The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). Ele é fornecido com dois argumentos:It is provided with two arguments:

  • Um Int32 valor que representa a contagem de iteração.An Int32 value that represents the iteration count.

  • Um ParallelLoopState instância que pode ser usada para interromper o loop prematuramente.A ParallelLoopState instance that can be used to break out of the loop prematurely. O ParallelLoopState objeto é criado pelo compilador; ele não pode ser instanciado no código do usuário.The ParallelLoopState object is created by the compiler; it cannot be instantiated in user code.

Chamar o Break método informa o for operação que não é necessário executar iterações depois do atual.Calling the Break method informs the for operation that iterations after the current one don't have to execute. No entanto, todas as iterações antes atual um ainda terá a ser executada se eles ainda não fez isso.However, all iterations before the current one will still have to be executed if they haven't already.

Portanto, chamar Break é semelhante ao uso de uma operação de interrupção dentro de um convencional for loop em uma linguagem como C#, mas não é um substituto perfeito: Por exemplo, não há nenhuma garantia de que iterações depois atual definitivamente não será executado.Therefore, calling Break is similar to using a break operation within a conventional for loop in a language like C#, but it is not a perfect substitute: For example, there is no guarantee that iterations after the current one will definitely not execute.

Se a execução de todas as iterações antes atual não é necessário, use o Stop método em vez de usar Break.If executing all iterations before the current one is not necessary, use the Stop method instead of using Break. Chamando Stop informa o for loop que ele pode abandonar restantes de todas as iterações, independentemente se eles estão antes ou após a iteração atual, porque todos os necessário trabalho será já tenha sido concluído.Calling Stop informs the for loop that it may abandon all remaining iterations, regardless of whether they're before or after the current iteration, because all required work will have already been completed. No entanto, como com Break, há nenhuma garantia em relação a quais outras iterações não serão executado.However, as with Break, there are no guarantees regarding which other iterations will not execute.

Se um loop é encerrado prematuramente, o ParallelLoopResult estrutura que é retornada conterá informações relevantes sobre a conclusão do loop.If a loop is ended prematurely, the ParallelLoopResult structure that is returned will contain relevant information about the loop's completion.

Se fromInclusive é maior que ou igual a toExclusive, o método retornará imediatamente sem executar qualquer iterações.If fromInclusive is greater than or equal to toExclusive, the method returns immediately without performing any iterations.

Veja também

For(Int32, Int32, Action<Int32>) For(Int32, Int32, Action<Int32>) For(Int32, Int32, Action<Int32>) For(Int32, Int32, Action<Int32>)

Executa um loop for (For no Visual Basic) no qual as iterações podem ser executadas em paralelo.Executes a for (For in Visual Basic) loop in which iterations may run in parallel.

public:
 static System::Threading::Tasks::ParallelLoopResult For(int fromInclusive, int toExclusive, Action<int> ^ body);
public static System.Threading.Tasks.ParallelLoopResult For (int fromInclusive, int toExclusive, Action<int> body);
static member For : int * int * Action<int> -> System.Threading.Tasks.ParallelLoopResult
Public Shared Function For (fromInclusive As Integer, toExclusive As Integer, body As Action(Of Integer)) As ParallelLoopResult

Parâmetros

fromInclusive
Int32 Int32 Int32 Int32

O índice inicial, inclusivo.The start index, inclusive.

toExclusive
Int32 Int32 Int32 Int32

O índice final, exclusivo.The end index, exclusive.

body
Action<Int32>

O delegado invocado uma vez por iteração.The delegate that is invoked once per iteration.

Retornos

Uma estrutura que contém informações sobre qual parte do loop foi concluída.A structure that contains information about which portion of the loop completed.

Exceções

O argumento body é null.The body argument is null.

A exceção que contém todas as exceções individuais lançadas em todos os threads.The exception that contains all the individual exceptions thrown on all threads.

Exemplos

O exemplo a seguir usa o For método 100 invocações de um delegado que gera bytes aleatórios de valores e computa sua soma.The following example uses the For method for 100 invocations of a delegate that generates random byte values and computes their sum.

using System;
using System.Threading.Tasks;

public class Example
{
   public static void Main()
   {
      ParallelLoopResult result = Parallel.For(0, 100, ctr => { Random rnd = new Random(ctr * 100000);
                                                                Byte[] bytes = new Byte[100];
                                                                rnd.NextBytes(bytes);
                                                                int sum = 0;
                                                                foreach(var byt in bytes)
                                                                    sum += byt;
                                                                Console.WriteLine("Iteration {0,2}: {1:N0}", ctr, sum);
                                                              });
      Console.WriteLine("Result: {0}", result.IsCompleted ? "Completed Normally" : 
                                                             String.Format("Completed to {0}", result.LowestBreakIteration));
   }
}
// The following is a portion of the output displayed by the example:
//       Iteration  0: 12,509
//       Iteration 50: 12,823
//       Iteration 51: 11,275
//       Iteration 52: 12,531
//       Iteration  1: 13,007
//       Iteration 53: 13,799
//       Iteration  4: 12,945
//       Iteration  2: 13,246
//       Iteration 54: 13,008
//       Iteration 55: 12,727
//       Iteration 56: 13,223
//       Iteration 57: 13,717
//       Iteration  5: 12,679
//       Iteration  3: 12,455
//       Iteration 58: 12,669
//       Iteration 59: 11,882
//       Iteration  6: 13,167
//       ...
//       Iteration 92: 12,275
//       Iteration 93: 13,282
//       Iteration 94: 12,745
//       Iteration 95: 11,957
//       Iteration 96: 12,455
//       Result: Completed Normally
Imports System.Threading.Tasks

Module Example
   Public Sub Main()
      Dim result As ParallelLoopResult = Parallel.For(0, 100, Sub(ctr)
                                                                 Dim rnd As New Random(ctr * 100000)
                                                                 Dim bytes(99) As Byte
                                                                 rnd.NextBytes(bytes)
                                                                 Dim sum As Integer
                                                                 For Each byt In bytes
                                                                    sum += byt
                                                                 Next
                                                                 Console.WriteLine("Iteration {0,2}: {1:N0}", ctr, sum)
                                                              End Sub)
      Console.WriteLine("Result: {0}", If(result.IsCompleted, "Completed Normally", 
                                                             String.Format("Completed to {0}", result.LowestBreakIteration)))
   End Sub
End Module
' The following is a portion of the output displayed by the example:
'       Iteration  0: 12,509
'       Iteration 50: 12,823
'       Iteration 51: 11,275
'       Iteration 52: 12,531
'       Iteration  1: 13,007
'       Iteration 53: 13,799
'       Iteration  4: 12,945
'       Iteration  2: 13,246
'       Iteration 54: 13,008
'       Iteration 55: 12,727
'       Iteration 56: 13,223
'       Iteration 57: 13,717
'       Iteration  5: 12,679
'       Iteration  3: 12,455
'       Iteration 58: 12,669
'       Iteration 59: 11,882
'       Iteration  6: 13,167
'       ...
'       Iteration 92: 12,275
'       Iteration 93: 13,282
'       Iteration 94: 12,745
'       Iteration 95: 11,957
'       Iteration 96: 12,455
'       Result: Completed Normally

Comentários

O body delegado é invocado uma vez para cada valor no intervalo de iteração (fromInclusive, toExclusive).The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). Ele é fornecido com a contagem de iteração (Int32) como um parâmetro.It is provided with the iteration count (Int32) as a parameter.

Se fromInclusive é maior que ou igual a toExclusive, o método retornará imediatamente sem executar qualquer iterações.If fromInclusive is greater than or equal to toExclusive, the method returns immediately without performing any iterations.

Veja também

For(Int64, Int64, Action<Int64,ParallelLoopState>) For(Int64, Int64, Action<Int64,ParallelLoopState>) For(Int64, Int64, Action<Int64,ParallelLoopState>) For(Int64, Int64, Action<Int64,ParallelLoopState>)

Executa um loop for (For no Visual Basic) com índices de 64 bits no qual as iterações podem ser executadas em paralelo e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop with 64-bit indexes in which iterations may run in parallel and the state of the loop can be monitored and manipulated.

public:
 static System::Threading::Tasks::ParallelLoopResult For(long fromInclusive, long toExclusive, Action<long, System::Threading::Tasks::ParallelLoopState ^> ^ body);
public static System.Threading.Tasks.ParallelLoopResult For (long fromInclusive, long toExclusive, Action<long,System.Threading.Tasks.ParallelLoopState> body);
static member For : int64 * int64 * Action<int64, System.Threading.Tasks.ParallelLoopState> -> System.Threading.Tasks.ParallelLoopResult
Public Shared Function For (fromInclusive As Long, toExclusive As Long, body As Action(Of Long, ParallelLoopState)) As ParallelLoopResult

Parâmetros

fromInclusive
Int64 Int64 Int64 Int64

O índice inicial, inclusivo.The start index, inclusive.

toExclusive
Int64 Int64 Int64 Int64

O índice final, exclusivo.The end index, exclusive.

body
Action<Int64,ParallelLoopState>

O delegado invocado uma vez por iteração.The delegate that is invoked once per iteration.

Retornos

Uma estrutura ParallelLoopResult que contém informações sobre qual parte do loop foi concluída.A ParallelLoopResult structure that contains information on what portion of the loop completed.

Exceções

O argumento body é null.The body argument is null.

A exceção que contém todas as exceções individuais lançadas em todos os threads.The exception that contains all the individual exceptions thrown on all threads.

Comentários

O body delegado é invocado uma vez para cada valor no intervalo de iteração (fromInclusive, toExclusive).The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). Ele é fornecido com os seguintes parâmetros: a contagem de iteração (Int64) e um ParallelLoopState instância que pode ser usada para interromper o loop prematuramente.It is provided with the following parameters: the iteration count (Int64), and a ParallelLoopState instance that may be used to break out of the loop prematurely.

Chamar o Break método informa o for operação que iterações depois do atual não tem a serem executadas, mas fazer todas as iterações antes do atual.Calling the Break method informs the for operation that iterations after the current one don't have to be executed, but all iterations before the current one do.

Portanto, chamar quebra é semelhante ao uso de uma operação de interrupção dentro de um convencional for loop em uma linguagem como C#, mas não é um substituto perfeito: Por exemplo, não há nenhuma garantia de que iterações depois atual definitivamente não será executado.Therefore, calling Break is similar to using a break operation within a conventional for loop in a language like C#, but it is not a perfect substitute: For example, there is no guarantee that iterations after the current one will definitely not execute.

Se a execução de todas as iterações antes atual não é necessário, use o Stop método em vez de usar Break.If executing all iterations before the current one is not necessary, use the Stop method instead of using Break. Chamando Stop informa o for loop que ele pode abandonar restantes de todas as iterações, independentemente se eles estão antes ou após a iteração atual, porque todos os necessário trabalho será já tenha sido concluído.Calling Stop informs the for loop that it may abandon all remaining iterations, regardless of whether they're before or after the current iteration, because all required work will have already been completed. No entanto, como com Break, há nenhuma garantia em relação a quais outras iterações não serão executado.However, as with Break, there are no guarantees regarding which other iterations will not execute.

Se um loop é encerrado prematuramente, o ParallelLoopResult estrutura que é retornada conterá informações relevantes sobre a conclusão do loop.If a loop is ended prematurely, the ParallelLoopResult structure that is returned will contain relevant information about the loop's completion.

Se fromInclusive é maior que ou igual a toExclusive, em seguida, o método retornará imediatamente sem executar qualquer iterações.If fromInclusive is greater than or equal to toExclusive, then the method returns immediately without performing any iterations.

Veja também

For(Int64, Int64, Action<Int64>) For(Int64, Int64, Action<Int64>) For(Int64, Int64, Action<Int64>) For(Int64, Int64, Action<Int64>)

Executa um loop for (For no Visual Basic) com índices de 64 bits no qual as iterações podem ser executadas em paralelo.Executes a for (For in Visual Basic) loop with 64-bit indexes in which iterations may run in parallel.

public:
 static System::Threading::Tasks::ParallelLoopResult For(long fromInclusive, long toExclusive, Action<long> ^ body);
public static System.Threading.Tasks.ParallelLoopResult For (long fromInclusive, long toExclusive, Action<long> body);
static member For : int64 * int64 * Action<int64> -> System.Threading.Tasks.ParallelLoopResult
Public Shared Function For (fromInclusive As Long, toExclusive As Long, body As Action(Of Long)) As ParallelLoopResult

Parâmetros

fromInclusive
Int64 Int64 Int64 Int64

O índice inicial, inclusivo.The start index, inclusive.

toExclusive
Int64 Int64 Int64 Int64

O índice final, exclusivo.The end index, exclusive.

body
Action<Int64>

O delegado invocado uma vez por iteração.The delegate that is invoked once per iteration.

Retornos

Uma estrutura que contém informações sobre qual parte do loop foi concluída.A structure that contains information about which portion of the loop completed.

Exceções

O argumento body é null.The body argument is null.

A exceção que contém todas as exceções individuais lançadas em todos os threads.The exception that contains all the individual exceptions thrown on all threads.

Comentários

O body delegado é invocado uma vez para cada valor no intervalo de iteração (fromInclusive, toExclusive).The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). Ele é fornecido com a contagem de iteração (Int64) como um parâmetro.It is provided with the iteration count (Int64) as a parameter.

Se fromInclusive é maior que ou igual a toExclusive, o método retornará imediatamente sem executar qualquer iterações.If fromInclusive is greater than or equal to toExclusive, the method returns immediately without performing any iterations.

Veja também

For(Int32, Int32, ParallelOptions, Action<Int32,ParallelLoopState>) For(Int32, Int32, ParallelOptions, Action<Int32,ParallelLoopState>) For(Int32, Int32, ParallelOptions, Action<Int32,ParallelLoopState>)

Executa um loop for (For no Visual Basic) no qual as iterações podem ser executadas em paralelo, as opções do loop podem ser configuradas e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop in which iterations may run in parallel, loop options can be configured, and the state of the loop can be monitored and manipulated.

public:
 static System::Threading::Tasks::ParallelLoopResult For(int fromInclusive, int toExclusive, System::Threading::Tasks::ParallelOptions ^ parallelOptions, Action<int, System::Threading::Tasks::ParallelLoopState ^> ^ body);
public static System.Threading.Tasks.ParallelLoopResult For (int fromInclusive, int toExclusive, System.Threading.Tasks.ParallelOptions parallelOptions, Action<int,System.Threading.Tasks.ParallelLoopState> body);
static member For : int * int * System.Threading.Tasks.ParallelOptions * Action<int, System.Threading.Tasks.ParallelLoopState> -> System.Threading.Tasks.ParallelLoopResult

Parâmetros

fromInclusive
Int32 Int32 Int32 Int32

O índice inicial, inclusivo.The start index, inclusive.

toExclusive
Int32 Int32 Int32 Int32

O índice final, exclusivo.The end index, exclusive.

parallelOptions
ParallelOptions ParallelOptions ParallelOptions ParallelOptions

Um objeto que configura o comportamento dessa operação.An object that configures the behavior of this operation.

body
Action<Int32,ParallelLoopState>

O delegado invocado uma vez por iteração.The delegate that is invoked once per iteration.

Retornos

Uma estrutura que contém informações sobre qual parte do loop foi concluída.A structure that contains information about which portion of the loop completed.

Exceções

O CancellationToken no argumento parallelOptions foi cancelado.The CancellationToken in the parallelOptions argument is canceled.

O argumento body é null.The body argument is null.

- ou --or- O argumento parallelOptions é null.The parallelOptions argument is null.

A exceção que contém todas as exceções individuais lançadas em todos os threads.The exception that contains all the individual exceptions thrown on all threads.

O CancellationTokenSource associado ao CancellationToken no parallelOptions foi descartado.The CancellationTokenSource associated with the CancellationToken in the parallelOptions has been disposed.

Comentários

O body delegado é invocado uma vez para cada valor no intervalo de iteração (fromInclusive, toExclusive).The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). Ele é fornecido com os seguintes parâmetros: a contagem de iteração (Int32) e um ParallelLoopState instância que pode ser usada para interromper o loop prematuramente.It is provided with the following parameters: the iteration count (Int32), and a ParallelLoopState instance that may be used to break out of the loop prematurely.

Se fromInclusive é maior que ou igual a toExclusive, o método retornará imediatamente sem executar qualquer iterações.If fromInclusive is greater than or equal to toExclusive, the method returns immediately without performing any iterations.

Veja também

For(Int32, Int32, ParallelOptions, Action<Int32>) For(Int32, Int32, ParallelOptions, Action<Int32>) For(Int32, Int32, ParallelOptions, Action<Int32>)

Executa um loop for (For no Visual Basic) em que as iterações podem ser executadas em paralelo e as opções de loop podem ser configuradas.Executes a for (For in Visual Basic) loop in which iterations may run in parallel and loop options can be configured.

public:
 static System::Threading::Tasks::ParallelLoopResult For(int fromInclusive, int toExclusive, System::Threading::Tasks::ParallelOptions ^ parallelOptions, Action<int> ^ body);
public static System.Threading.Tasks.ParallelLoopResult For (int fromInclusive, int toExclusive, System.Threading.Tasks.ParallelOptions parallelOptions, Action<int> body);
static member For : int * int * System.Threading.Tasks.ParallelOptions * Action<int> -> System.Threading.Tasks.ParallelLoopResult

Parâmetros

fromInclusive
Int32 Int32 Int32 Int32

O índice inicial, inclusivo.The start index, inclusive.

toExclusive
Int32 Int32 Int32 Int32

O índice final, exclusivo.The end index, exclusive.

parallelOptions
ParallelOptions ParallelOptions ParallelOptions ParallelOptions

Um objeto que configura o comportamento dessa operação.An object that configures the behavior of this operation.

body
Action<Int32>

O delegado invocado uma vez por iteração.The delegate that is invoked once per iteration.

Retornos

Uma estrutura que contém informações sobre qual parte do loop foi concluída.A structure that contains information about which portion of the loop completed.

Exceções

O CancellationToken no argumento parallelOptions foi cancelado.The CancellationToken in the parallelOptions argument is canceled.

O argumento body é null.The body argument is null.

- ou --or- O argumento parallelOptions é null.The parallelOptions argument is null.

A exceção que contém todas as exceções individuais lançadas em todos os threads.The exception that contains all the individual exceptions thrown on all threads.

O CancellationTokenSource associado ao CancellationToken no parallelOptions foi descartado.The CancellationTokenSource associated with the CancellationToken in the parallelOptions has been disposed.

Exemplos

O exemplo a seguir mostra como cancelar um loop paralelo:The following example shows how to cancel a parallel loop:



using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

class ParallelForCancellation
{
    // Demonstrated features:
    //		CancellationTokenSource
    // 		Parallel.For()
    //		ParallelOptions
    //		ParallelLoopResult
    // Expected results:
    // 		An iteration for each argument value (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) is executed.
    //		The order of execution of the iterations is undefined.
    //		The iteration when i=2 cancels the loop.
    //		Some iterations may bail out or not start at all; because they are temporally executed in unpredictable order, 
    //          it is impossible to say which will start/complete and which won't.
    //		At the end, an OperationCancelledException is surfaced.
    // Documentation:
    //		http://msdn.microsoft.com/library/system.threading.cancellationtokensource(VS.100).aspx
    static void CancelDemo()
    {
        CancellationTokenSource cancellationSource = new CancellationTokenSource();
        ParallelOptions options = new ParallelOptions();
        options.CancellationToken = cancellationSource.Token;

        try
        {
            ParallelLoopResult loopResult = Parallel.For(
                    0,
                    10,
                    options,
                    (i, loopState) =>
                    {
                        Console.WriteLine("Start Thread={0}, i={1}", Thread.CurrentThread.ManagedThreadId, i);

                        // Simulate a cancellation of the loop when i=2
                        if (i == 2)
                        {
                            cancellationSource.Cancel();
                        }

                        // Simulates a long execution
                        for (int j = 0; j < 10; j++)
                        {
                            Thread.Sleep(1 * 200);

                            // check to see whether or not to continue
                            if (loopState.ShouldExitCurrentIteration) return;
                        }

                        Console.WriteLine("Finish Thread={0}, i={1}", Thread.CurrentThread.ManagedThreadId, i);
                    }
                );

            if (loopResult.IsCompleted)
            {
                Console.WriteLine("All iterations completed successfully. THIS WAS NOT EXPECTED.");
            }
        }
        // No exception is expected in this example, but if one is still thrown from a task,
        // it will be wrapped in AggregateException and propagated to the main thread.
        catch (AggregateException e)
        {
            Console.WriteLine("Parallel.For has thrown an AggregateException. THIS WAS NOT EXPECTED.\n{0}", e);
        }
        // Catching the cancellation exception
        catch (OperationCanceledException e)
        {
            Console.WriteLine("An iteration has triggered a cancellation. THIS WAS EXPECTED.\n{0}", e.ToString());
        }
        finally
        {
           cancellationSource.Dispose();
        }
    }
}
Imports System.Threading
Imports System.Threading.Tasks

Module LoopCancellation
    ' Demonstrated features:
    '   CancellationTokenSource
    '   Parallel.For()
    '   ParallelOptions
    '   ParallelLoopResult
    ' Expected results:
    '   An iteration for each argument value (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) is executed.
    '   The order of execution of the iterations is undefined.
    '   The iteration when i=2 cancels the loop.
    '   Some iterations may bail out or not start at all; because they are temporally executed in unpredictable order, 
    '      it is impossible to say which will start/complete and which won't.
    '   At the end, an OperationCancelledException is surfaced.
    ' Documentation:
    '   http://msdn.microsoft.com/library/system.threading.cancellationtokensource(VS.100).aspx
    Private Sub Main()
        Dim cancellationSource As New CancellationTokenSource()
        Dim options As New ParallelOptions()
        options.CancellationToken = cancellationSource.Token

        Try
            Dim loopResult As ParallelLoopResult = _
                Parallel.For(0, 10, options, Sub(i, loopState)
                                                 Console.WriteLine("Start Thread={0}, i={1}", Thread.CurrentThread.ManagedThreadId, i)

                                                 ' Simulate a cancellation of the loop when i=2
                                                 If i = 2 Then
                                                     cancellationSource.Cancel()
                                                 End If

                                                 ' Simulates a long execution
                                                 For j As Integer = 0 To 9
                                                     Thread.Sleep(1 * 200)

                                                     ' check to see whether or not to continue
                                                     If loopState.ShouldExitCurrentIteration Then
                                                         Exit Sub
                                                     End If
                                                 Next

                                                 Console.WriteLine("Finish Thread={0}, i={1}", Thread.CurrentThread.ManagedThreadId, i)
                                             End Sub)

            If loopResult.IsCompleted Then
                Console.WriteLine("All iterations completed successfully. THIS WAS NOT EXPECTED.")
            End If
        Catch e As AggregateException
            ' No exception is expected in this example, but if one is still thrown from a task,
            ' it will be wrapped in AggregateException and propagated to the main thread.
            Console.WriteLine("An action has thrown an AggregateException. THIS WAS NOT EXPECTED." & vbLf & "{0}", e)
        Catch e As OperationCanceledException
            ' Catching the cancellation exception
            Console.WriteLine("An iteration has triggered a cancellation. THIS WAS EXPECTED." & vbLf & "{0}", e)
        Finally
            cancellationSource.Dispose()
        End Try
    End Sub
End Module

Comentários

O body delegado é invocado uma vez para cada valor no intervalo de iteração (fromInclusive, toExclusive).The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). Ele é fornecido com a contagem de iteração (Int32) como um parâmetro.It is provided with the iteration count (Int32) as a parameter.

Se fromInclusive é maior que ou igual a toExclusive, em seguida, o método retornará imediatamente sem executar qualquer iterações.If fromInclusive is greater than or equal to toExclusive, then the method returns immediately without performing any iterations.

Veja também

For(Int64, Int64, ParallelOptions, Action<Int64,ParallelLoopState>) For(Int64, Int64, ParallelOptions, Action<Int64,ParallelLoopState>) For(Int64, Int64, ParallelOptions, Action<Int64,ParallelLoopState>)

Executa um loop for (For no Visual Basic) com índices de 64 bits no qual iterações podem ser executadas em paralelo, opções de loop podem ser configuradas e o estado de loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop with 64-bit indexes in which iterations may run in parallel, loop options can be configured, and the state of the loop can be monitored and manipulated.

public:
 static System::Threading::Tasks::ParallelLoopResult For(long fromInclusive, long toExclusive, System::Threading::Tasks::ParallelOptions ^ parallelOptions, Action<long, System::Threading::Tasks::ParallelLoopState ^> ^ body);
public static System.Threading.Tasks.ParallelLoopResult For (long fromInclusive, long toExclusive, System.Threading.Tasks.ParallelOptions parallelOptions, Action<long,System.Threading.Tasks.ParallelLoopState> body);
static member For : int64 * int64 * System.Threading.Tasks.ParallelOptions * Action<int64, System.Threading.Tasks.ParallelLoopState> -> System.Threading.Tasks.ParallelLoopResult

Parâmetros

fromInclusive
Int64 Int64 Int64 Int64

O índice inicial, inclusivo.The start index, inclusive.

toExclusive
Int64 Int64 Int64 Int64

O índice final, exclusivo.The end index, exclusive.

parallelOptions
ParallelOptions ParallelOptions ParallelOptions ParallelOptions

Um objeto que configura o comportamento dessa operação.An object that configures the behavior of this operation.

body
Action<Int64,ParallelLoopState>

O delegado invocado uma vez por iteração.The delegate that is invoked once per iteration.

Retornos

Uma estrutura que contém informações sobre qual parte do loop foi concluída.A structure that contains information about which portion of the loop completed.

Exceções

O CancellationToken no argumento parallelOptions foi cancelado.The CancellationToken in the parallelOptions argument is canceled.

O argumento body é null.The body argument is null.

- ou --or- O argumento parallelOptions é null.The parallelOptions argument is null.

A exceção que contém todas as exceções individuais lançadas em todos os threads.The exception that contains all the individual exceptions thrown on all threads.

O CancellationTokenSource associado ao CancellationToken no parallelOptions foi descartado.The CancellationTokenSource associated with the CancellationToken in the parallelOptions has been disposed.

Exemplos

O exemplo a seguir mostra como usar o Parallel.For método com um ParallelOptions objeto:The following example shows how to use the Parallel.For method with a ParallelOptions object:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;


class ParallelOptionsDemo
{
    // Demonstrated features:
    // 		Parallel.For()
    //		ParallelOptions
    // Expected results:
    // 		An iteration for each argument value (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) is executed.
    //		The order of execution of the iterations is undefined.
    //		Verify that no more than two threads have been used for the iterations.
    // Documentation:
    //		http://msdn.microsoft.com/library/system.threading.tasks.parallel.for(VS.100).aspx
    static void Main()
    {
        ParallelOptions options = new ParallelOptions();
        options.MaxDegreeOfParallelism = 2; // -1 is for unlimited. 1 is for sequential.

        try
        {
            Parallel.For(
                    0,
                    9,
                    options,
                    (i) =>
                    {
                        Console.WriteLine("Thread={0}, i={1}", Thread.CurrentThread.ManagedThreadId, i);
                    }
                );

        }
        // No exception is expected in this example, but if one is still thrown from a task,
        // it will be wrapped in AggregateException and propagated to the main thread.
        catch (AggregateException e)
        {
            Console.WriteLine("Parallel.For has thrown the following (unexpected) exception:\n{0}", e);
        }
    }

}


Imports System.Threading
Imports System.Threading.Tasks


Module ParallelForDemo

    ' Demonstrated features:
    '   Parallel.For()
    '   ParallelOptions
    ' Expected results:
    '   An iteration for each argument value (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) is executed.
    '   The order of execution of the iterations is undefined.
    '   Verify that no more than two threads have been used for the iterations.
    ' Documentation:
    '   http://msdn.microsoft.com/library/system.threading.tasks.parallel.for(VS.100).aspx
    Sub Main()
        Dim options As New ParallelOptions()
        options.MaxDegreeOfParallelism = 2 ' -1 is for unlimited. 1 is for sequential.
        Try
            Parallel.For(0, 9, options, Sub(i)
                                            Console.WriteLine("Thread={0}, i={1}", Thread.CurrentThread.ManagedThreadId, i)

                                        End Sub)
        Catch e As AggregateException
            ' No exception is expected in this example, but if one is still thrown from a task,
            ' it will be wrapped in AggregateException and propagated to the main thread.
            Console.WriteLine("Parallel.For has thrown the following (unexpected) exception:" & vbLf & "{0}", e)
        End Try
    End Sub

End Module

Comentários

O body delegado é invocado uma vez para cada valor no intervalo de iteração (fromInclusive, toExclusive).The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). Ele é fornecido com os seguintes parâmetros: a contagem de iteração (Int64) e um ParallelLoopState instância que pode ser usada para interromper o loop prematuramente.It is provided with the following parameters: the iteration count (Int64), and a ParallelLoopState instance that may be used to break out of the loop prematurely.

Se fromInclusive é maior que ou igual a toExclusive, o método retornará imediatamente sem executar qualquer iterações.If fromInclusive is greater than or equal to toExclusive, the method returns immediately without performing any iterations.

Veja também

For(Int64, Int64, ParallelOptions, Action<Int64>) For(Int64, Int64, ParallelOptions, Action<Int64>) For(Int64, Int64, ParallelOptions, Action<Int64>)

Executa um loop for (For no Visual Basic) com índices de 64 bits no qual as iterações podem ser executadas em paralelo e opções de loop podem ser configuradas.Executes a for (For in Visual Basic) loop with 64-bit indexes in which iterations may run in parallel and loop options can be configured.

public:
 static System::Threading::Tasks::ParallelLoopResult For(long fromInclusive, long toExclusive, System::Threading::Tasks::ParallelOptions ^ parallelOptions, Action<long> ^ body);
public static System.Threading.Tasks.ParallelLoopResult For (long fromInclusive, long toExclusive, System.Threading.Tasks.ParallelOptions parallelOptions, Action<long> body);
static member For : int64 * int64 * System.Threading.Tasks.ParallelOptions * Action<int64> -> System.Threading.Tasks.ParallelLoopResult

Parâmetros

fromInclusive
Int64 Int64 Int64 Int64

O índice inicial, inclusivo.The start index, inclusive.

toExclusive
Int64 Int64 Int64 Int64

O índice final, exclusivo.The end index, exclusive.

parallelOptions
ParallelOptions ParallelOptions ParallelOptions ParallelOptions

Um objeto que configura o comportamento dessa operação.An object that configures the behavior of this operation.

body
Action<Int64>

O delegado invocado uma vez por iteração.The delegate that is invoked once per iteration.

Retornos

Uma estrutura que contém informações sobre qual parte do loop foi concluída.A structure that contains information about which portion of the loop completed.

Exceções

O CancellationToken no argumento parallelOptions foi cancelado.The CancellationToken in the parallelOptions argument is canceled.

O argumento body é null.The body argument is null.

- ou --or- O argumento parallelOptions é null.The parallelOptions argument is null.

A exceção que contém todas as exceções individuais lançadas em todos os threads.The exception that contains all the individual exceptions thrown on all threads.

O CancellationTokenSource associado ao CancellationToken no parallelOptions foi descartado.The CancellationTokenSource associated with the CancellationToken in the parallelOptions has been disposed.

Exemplos

O exemplo a seguir mostra como usar ParallelOptions para especificar um agendador de tarefas personalizados:The following example shows how to use ParallelOptions to specify a custom task scheduler:

using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

class ParallelSchedulerDemo2
{
        // Demonstrated features:
        //		TaskScheduler
        //      BlockingCollection
        // 		Parallel.For()
        //		ParallelOptions
        // Expected results:
        // 		An iteration for each argument value (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) is executed.
        //		The TwoThreadTaskScheduler employs 2 threads on which iterations may be executed in a random order.
        //		Thus a scheduler thread may execute multiple iterations.
        // Documentation:
        //		http://msdn.microsoft.com/library/system.threading.tasks.taskscheduler(VS.100).aspx
        //		http://msdn.microsoft.com/library/dd997413(VS.100).aspx
        // More information:
        //		http://blogs.msdn.com/pfxteam/archive/2009/09/22/9898090.aspx
        static void Main()
        {
            ParallelOptions options = new ParallelOptions();

            // Construct and associate a custom task scheduler
            options.TaskScheduler = new TwoThreadTaskScheduler();

            try
            {
                Parallel.For(
                        0,
                        10,
                        options,
                        (i, localState) =>
                        {
                            Console.WriteLine("i={0}, Task={1}, Thread={2}", i, Task.CurrentId, Thread.CurrentThread.ManagedThreadId);
                        }
                    );

            }
            // No exception is expected in this example, but if one is still thrown from a task,
            // it will be wrapped in AggregateException and propagated to the main thread.
            catch (AggregateException e)
            {
                Console.WriteLine("An iteration has thrown an exception. THIS WAS NOT EXPECTED.\n{0}", e);
            }
        }

        // This scheduler schedules all tasks on (at most) two threads
        sealed class TwoThreadTaskScheduler : TaskScheduler, IDisposable
        {
            // The runtime decides how many tasks to create for the given set of iterations, loop options, and scheduler's max concurrency level.
            // Tasks will be queued in this collection
            private BlockingCollection<Task> _tasks = new BlockingCollection<Task>();

            // Maintain an array of threads. (Feel free to bump up _n.)
            private readonly int _n = 2;
            private Thread[] _threads;

            public TwoThreadTaskScheduler()
            {
                _threads = new Thread[_n];

                // Create unstarted threads based on the same inline delegate
                for (int i = 0; i < _n; i++)
                {
                    _threads[i] = new Thread(() =>
                    {
                        // The following loop blocks until items become available in the blocking collection.
                        // Then one thread is unblocked to consume that item.
                        foreach (var task in _tasks.GetConsumingEnumerable())
                        {
                            TryExecuteTask(task);
                        }
                    });

                    // Start each thread
                    _threads[i].IsBackground = true;
                    _threads[i].Start();
                }
            }

            // This method is invoked by the runtime to schedule a task
            protected override void QueueTask(Task task)
            {
                _tasks.Add(task);
            }

            // The runtime will probe if a task can be executed in the current thread.
            // By returning false, we direct all tasks to be queued up.
            protected override bool TryExecuteTaskInline(Task task, bool taskWasPreviouslyQueued)
            {
                return false;
            }

            public override int MaximumConcurrencyLevel { get { return _n; } }

            protected override IEnumerable<Task> GetScheduledTasks()
            {
                return _tasks.ToArray();
            }

            // Dispose is not thread-safe with other members.
            // It may only be used when no more tasks will be queued
            // to the scheduler.  This implementation will block
            // until all previously queued tasks have completed.
            public void Dispose()
            {
                if (_threads != null)
                {
                    _tasks.CompleteAdding();

                    for (int i = 0; i < _n; i++)
                    {
                        _threads[i].Join();
                        _threads[i] = null;
                    }
                    _threads = null;
                    _tasks.Dispose();
                    _tasks = null;
                }
            }
        

    }
}
Imports System.Collections.Concurrent
Imports System.Threading
Imports System.Threading.Tasks
Module SchedulerDemo
    ' Demonstrated features:
    '   TaskScheduler
    '   BlockingCollection
    '   Parallel.For()
    '   ParallelOptions
    ' Expected results:
    '   An iteration for each argument value (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) is executed.
    '   The TwoThreadTaskScheduler employs 2 threads on which iterations may be executed in a random order.
    '   A task is internally created for each thread of the task scheduler (plus an aditional internal task).
    '	Thus a scheduler thread may execute multiple iterations.
    ' Documentation:
    '   http://msdn.microsoft.com/library/system.threading.tasks.taskscheduler(VS.100).aspx
    '   http://msdn.microsoft.com/library/dd997413(VS.100).aspx
    ' More information:
    '   http://blogs.msdn.com/pfxteam/archive/2009/09/22/9898090.aspx
    Sub Main()
        Dim options As New ParallelOptions()

        ' Construct and associate a custom task scheduler
        options.TaskScheduler = New TwoThreadTaskScheduler()

        Try
            Parallel.For(0, 10, options, Sub(i, localState)
                                             Console.WriteLine("i={0}, Task={1}, Thread={2}", i, Task.CurrentId, Thread.CurrentThread.ManagedThreadId)

                                         End Sub)
        Catch e As AggregateException
            ' No exception is expected in this example, but if one is still thrown from a task,
            ' it will be wrapped in AggregateException and propagated to the main thread.
            Console.WriteLine("An iteration has thrown an exception. THIS WAS NOT EXPECTED." & vbLf & "{0}", e)
        End Try
    End Sub

    ' This scheduler schedules all tasks on (at most) two threads
    Private NotInheritable Class TwoThreadTaskScheduler
        Inherits TaskScheduler
        Implements IDisposable
        ' The runtime decides how many tasks to create for the given set of iterations, loop options, and scheduler's max concurrency level.
        ' Tasks will be queued in this collection
        Private _tasks As New BlockingCollection(Of Task)()

        ' Maintain an array of threads. (Feel free to bump up _n.)
        Private ReadOnly _n As Integer = 2
        Private _threads As Thread()

        Public Sub New()
            _threads = New Thread(_n - 1) {}

            ' Create unstarted threads based on the same inline delegate
            For i As Integer = 0 To _n - 1
                _threads(i) = New Thread(Sub()
                                             ' The following loop blocks until items become available in the blocking collection.
                                             ' Then one thread is unblocked to consume that item.
                                             For Each task In _tasks.GetConsumingEnumerable()
                                                 TryExecuteTask(task)
                                             Next
                                         End Sub)

                ' Start each thread
                _threads(i).IsBackground = True
                _threads(i).Start()
            Next
        End Sub

        ' This method is invoked by the runtime to schedule a task
        Protected Overloads Overrides Sub QueueTask(ByVal task As Task)
            _tasks.Add(task)
        End Sub

        ' The runtime will probe if a task can be executed in the current thread.
        ' By returning false, we direct all tasks to be queued up.
        Protected Overloads Overrides Function TryExecuteTaskInline(ByVal task As Task, ByVal taskWasPreviouslyQueued As Boolean) As Boolean
            Return False
        End Function

        Public Overloads Overrides ReadOnly Property MaximumConcurrencyLevel() As Integer
            Get
                Return _n
            End Get
        End Property

        Protected Overloads Overrides Function GetScheduledTasks() As IEnumerable(Of Task)
            Return _tasks.ToArray()
        End Function

        ' Dispose is not thread-safe with other members.
        ' It may only be used when no more tasks will be queued
        ' to the scheduler. This implementation will block
        ' until all previously queued tasks have completed.
        Public Sub Dispose() Implements IDisposable.Dispose
            If _threads IsNot Nothing Then
                _tasks.CompleteAdding()

                For i As Integer = 0 To _n - 1
                    _threads(i).Join()
                    _threads(i) = Nothing
                Next
                _threads = Nothing
                _tasks.Dispose()
                _tasks = Nothing
            End If
        End Sub
    End Class

End Module

Comentários

Dá suporte a índices de 64 bits.Supports 64-bit indexes. O body delegado é invocado uma vez para cada valor no intervalo de iteração (fromInclusive, toExclusive).The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). Ele é fornecido com a contagem de iteração (Int64) como um parâmetro.It is provided with the iteration count (Int64) as a parameter.

Se fromInclusive é maior que ou igual a toExclusive, em seguida, o método retornará imediatamente sem executar qualquer iterações.If fromInclusive is greater than or equal to toExclusive, then the method returns immediately without performing any iterations.

Veja também

For<TLocal>(Int64, Int64, ParallelOptions, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int64, Int64, ParallelOptions, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int64, Int64, ParallelOptions, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>)

Executa um loop for (For no Visual Basic) com índices de 64 bits e dados locais do thread nos quais iterações podem ser executadas em paralelo, opções de loop podem ser configuradas e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop with 64-bit indexes and thread-local data in which iterations may run in parallel, loop options can be configured, and the state of the loop can be monitored and manipulated.

public:
generic <typename TLocal>
 static System::Threading::Tasks::ParallelLoopResult For(long fromInclusive, long toExclusive, System::Threading::Tasks::ParallelOptions ^ parallelOptions, Func<TLocal> ^ localInit, Func<long, System::Threading::Tasks::ParallelLoopState ^, TLocal, TLocal> ^ body, Action<TLocal> ^ localFinally);
public static System.Threading.Tasks.ParallelLoopResult For<TLocal> (long fromInclusive, long toExclusive, System.Threading.Tasks.ParallelOptions parallelOptions, Func<TLocal> localInit, Func<long,System.Threading.Tasks.ParallelLoopState,TLocal,TLocal> body, Action<TLocal> localFinally);
static member For : int64 * int64 * System.Threading.Tasks.ParallelOptions * Func<'Local> * Func<int64, System.Threading.Tasks.ParallelLoopState, 'Local, 'Local> * Action<'Local> -> System.Threading.Tasks.ParallelLoopResult

Parâmetros de tipo

TLocal

O tipo dos dados locais do thread.The type of the thread-local data.

Parâmetros

fromInclusive
Int64 Int64 Int64 Int64

O índice inicial, inclusivo.The start index, inclusive.

toExclusive
Int64 Int64 Int64 Int64

O índice final, exclusivo.The end index, exclusive.

parallelOptions
ParallelOptions ParallelOptions ParallelOptions ParallelOptions

Um objeto que configura o comportamento dessa operação.An object that configures the behavior of this operation.

localInit
Func<TLocal>

O delegado da função que retorna o estado inicial dos dados locais para cada thread.The function delegate that returns the initial state of the local data for each thread.

body
Func<Int64,ParallelLoopState,TLocal,TLocal>

O delegado invocado uma vez por iteração.The delegate that is invoked once per iteration.

localFinally
Action<TLocal>

O delegado que executa uma ação final no estado local de cada thread.The delegate that performs a final action on the local state of each thread.

Retornos

Uma estrutura que contém informações sobre qual parte do loop foi concluída.A structure that contains information about which portion of the loop completed.

Exceções

O argumento body é null.The body argument is null.

- ou --or- O argumento localInit é null.The localInit argument is null.

- ou --or- O argumento localFinally é null.The localFinally argument is null.

- ou --or- O argumento parallelOptions é null.The parallelOptions argument is null.

O CancellationToken no argumento parallelOptions foi cancelado.The CancellationToken in the parallelOptions argument is canceled.

O CancellationTokenSource associado ao CancellationToken no parallelOptions foi descartado.The CancellationTokenSource associated with the CancellationToken in the parallelOptions has been disposed.

A exceção que contém todas as exceções individuais lançadas em todos os threads.The exception that contains all the individual exceptions thrown on all threads.

Comentários

O body delegado é invocado uma vez para cada valor no intervalo de iteração (fromInclusive, toExclusive).The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). Ele é fornecido com os seguintes parâmetros: a contagem de iteração (Int64), um ParallelLoopState instância que pode ser usada para interromper o loop prematuramente e alguns estados de locais que podem ser compartilhados entre as iterações que executam no mesmo thread.It is provided with the following parameters: the iteration count (Int64), a ParallelLoopState instance that may be used to break out of the loop prematurely, and some local state that may be shared amongst iterations that execute on the same thread.

O localInit delegado é invocado uma vez para cada thread que participa da execução do loop e retorna o estado local inicial para cada um desses segmentos.The localInit delegate is invoked once for each thread that participates in the loop's execution and returns the initial local state for each of those threads. Esses estados iniciais são passados para o primeiro body invocações em cada thread.These initial states are passed to the first body invocations on each thread. Em seguida, cada invocação subsequente corpo retorna um valor de estado possivelmente modificado que é passado para a próxima invocação de corpo.Then, every subsequent body invocation returns a possibly modified state value that is passed to the next body invocation. Por fim, a última chamada do corpo em cada thread retorna um valor de estado que é passado para o localFinally delegar.Finally, the last body invocation on each thread returns a state value that is passed to the localFinally delegate. O localFinally delegado é invocado uma vez por thread para executar uma ação final no estado local de cada thread.The localFinally delegate is invoked once per thread to perform a final action on each thread's local state. Esse delegado pode ser invocado simultaneamente em vários threads; Portanto, você deve sincronizar o acesso a quaisquer variáveis compartilhadas.This delegate might be invoked concurrently on multiple threads; therefore, you must synchronize access to any shared variables.

O Parallel.For método pode usar tarefas mais do que os threads durante a vida útil de sua execução, como as tarefas existentes são concluídas e são substituídas por novas tarefas.The Parallel.For method may use more tasks than threads over the lifetime of its execution, as existing tasks complete and are replaced by new tasks. Isso proporciona subjacente TaskScheduler do objeto a chance de adicionar, alterar ou remover threads que o loop de serviço.This gives the underlying TaskScheduler object the chance to add, change, or remove threads that service the loop.

Se fromInclusive é maior que ou igual a toExclusive, em seguida, o método retornará imediatamente sem executar qualquer iterações.If fromInclusive is greater than or equal to toExclusive, then the method returns immediately without performing any iterations.

Veja também

For<TLocal>(Int32, Int32, ParallelOptions, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int32, Int32, ParallelOptions, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int32, Int32, ParallelOptions, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>)

Executa um loop for (For no Visual Basic) com os dados locais do thread nos quais iterações podem ser executadas em paralelo, opções de loop podem ser configuradas e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop with thread-local data in which iterations may run in parallel, loop options can be configured, and the state of the loop can be monitored and manipulated.

public:
generic <typename TLocal>
 static System::Threading::Tasks::ParallelLoopResult For(int fromInclusive, int toExclusive, System::Threading::Tasks::ParallelOptions ^ parallelOptions, Func<TLocal> ^ localInit, Func<int, System::Threading::Tasks::ParallelLoopState ^, TLocal, TLocal> ^ body, Action<TLocal> ^ localFinally);
public static System.Threading.Tasks.ParallelLoopResult For<TLocal> (int fromInclusive, int toExclusive, System.Threading.Tasks.ParallelOptions parallelOptions, Func<TLocal> localInit, Func<int,System.Threading.Tasks.ParallelLoopState,TLocal,TLocal> body, Action<TLocal> localFinally);
static member For : int * int * System.Threading.Tasks.ParallelOptions * Func<'Local> * Func<int, System.Threading.Tasks.ParallelLoopState, 'Local, 'Local> * Action<'Local> -> System.Threading.Tasks.ParallelLoopResult

Parâmetros de tipo

TLocal

O tipo dos dados locais do thread.The type of the thread-local data.

Parâmetros

fromInclusive
Int32 Int32 Int32 Int32

O índice inicial, inclusivo.The start index, inclusive.

toExclusive
Int32 Int32 Int32 Int32

O índice final, exclusivo.The end index, exclusive.

parallelOptions
ParallelOptions ParallelOptions ParallelOptions ParallelOptions

Um objeto que configura o comportamento dessa operação.An object that configures the behavior of this operation.

localInit
Func<TLocal>

O delegado da função que retorna o estado inicial dos dados locais para cada tarefa.The function delegate that returns the initial state of the local data for each task.

body
Func<Int32,ParallelLoopState,TLocal,TLocal>

O delegado invocado uma vez por iteração.The delegate that is invoked once per iteration.

localFinally
Action<TLocal>

O delegado que executa uma ação final no estado local de cada tarefa.The delegate that performs a final action on the local state of each task.

Retornos

Uma estrutura que contém informações sobre qual parte do loop foi concluída.A structure that contains information about which portion of the loop completed.

Exceções

O argumento body é null.The body argument is null.

- ou --or- O argumento localInit é null.The localInit argument is null.

- ou --or- O argumento localFinally é null.The localFinally argument is null.

- ou --or- O argumento parallelOptions é null.The parallelOptions argument is null.

O CancellationToken no argumento parallelOptions foi cancelado.The CancellationToken in the parallelOptions argument is canceled.

O CancellationTokenSource associado ao CancellationToken no parallelOptions foi descartado.The CancellationTokenSource associated with the CancellationToken in the parallelOptions has been disposed.

A exceção que contém todas as exceções individuais lançadas em todos os threads.The exception that contains all the individual exceptions thrown on all threads.

Exemplos

O exemplo a seguir usa as variáveis locais de thread para calcular a soma dos resultados de muitas operações demoradas.The following example uses thread-local variables to compute the sum of the results of many lengthy operations. Este exemplo limita o grau de paralelismo para quatro.This example limits the degree of parallelism to four.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

class ThreadLocalForWithOptions
{
   // The number of parallel iterations to perform.
   const int N = 1000000;

   static void Main()
   {
      // The result of all thread-local computations.
      int result = 0;

      // This example limits the degree of parallelism to four.
      // You might limit the degree of parallelism when your algorithm
      // does not scale beyond a certain number of cores or when you 
      // enforce a particular quality of service in your application.

      Parallel.For(0, N, new ParallelOptions { MaxDegreeOfParallelism = 4 },
         // Initialize the local states
         () => 0,
         // Accumulate the thread-local computations in the loop body
         (i, loop, localState) =>
         {
            return localState + Compute(i);
         },
         // Combine all local states
         localState => Interlocked.Add(ref result, localState)
      );

      // Print the actual and expected results.
      Console.WriteLine("Actual result: {0}. Expected 1000000.", result);
   }

   // Simulates a lengthy operation.
   private static int Compute(int n)
   {
      for (int i = 0; i < 10000; i++) ;
      return 1;
   }
}
Imports System.Threading
Imports System.Threading.Tasks

Module ThreadLocalForWithOptions

   ' The number of parallel iterations to perform.
   Const N As Integer = 1000000

   Sub Main()
      ' The result of all thread-local computations.
      Dim result As Integer = 0

      ' This example limits the degree of parallelism to four.
      ' You might limit the degree of parallelism when your algorithm
      ' does not scale beyond a certain number of cores or when you 
      ' enforce a particular quality of service in your application.

      Parallel.For(0, N, New ParallelOptions With {.MaxDegreeOfParallelism = 4},
         Function()
            ' Initialize the local states 
            Return 0
         End Function,
         Function(i, loopState, localState)
            ' Accumulate the thread-local computations in the loop body
            Return localState + Compute(i)
         End Function,
         Sub(localState)
            ' Combine all local states
            Interlocked.Add(result, localState)
         End Sub
      )

      ' Print the actual and expected results.
      Console.WriteLine("Actual result: {0}. Expected 1000000.", result)
   End Sub

   ' Simulates a lengthy operation.
   Function Compute(ByVal n As Integer) As Integer
      For i As Integer = 0 To 10000
      Next
      Return 1
   End Function
End Module

Comentários

O body delegado é invocado uma vez para cada valor no intervalo de iteração (fromInclusive, toExclusive).The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). Ele é fornecido com os seguintes parâmetros: a contagem de iteração (Int32), um ParallelLoopState instância que pode ser usada para interromper o loop prematuramente e alguns estados de locais que podem ser compartilhados entre as iterações que são executados na mesma tarefa.It is provided with the following parameters: the iteration count (Int32), a ParallelLoopState instance that may be used to break out of the loop prematurely, and some local state that may be shared amongst iterations that execute on the same task.

O localInit delegado é invocado uma vez para cada tarefa que participa de execução do loop e retorna o estado local inicial para cada uma dessas tarefas.The localInit delegate is invoked once for each task that participates in the loop's execution and returns the initial local state for each of those tasks. Esses estados iniciais são passados para o primeiro body invocações em cada tarefa.These initial states are passed to the first body invocations on each task. Em seguida, cada invocação subsequente corpo retorna um valor de estado possivelmente modificado que é passado para a próxima invocação de corpo.Then, every subsequent body invocation returns a possibly modified state value that is passed to the next body invocation. Por fim, a última chamada do corpo em cada tarefa retorna um valor de estado que é passado para o localFinally delegar.Finally, the last body invocation on each task returns a state value that is passed to the localFinally delegate. O localFinally delegado é invocado uma vez por tarefa para executar uma ação final no estado local de cada tarefa.The localFinally delegate is invoked once per task to perform a final action on each task's local state. Esse delegado pode ser invocado simultaneamente em vários threads; Portanto, você deve sincronizar o acesso a quaisquer variáveis compartilhadas.This delegate might be invoked concurrently on multiple threads; therefore, you must synchronize access to any shared variables.

O Parallel.For método pode usar tarefas mais do que os threads durante a vida útil de sua execução, como as tarefas existentes são concluídas e são substituídas por novas tarefas.The Parallel.For method may use more tasks than threads over the lifetime of its execution, as existing tasks complete and are replaced by new tasks. Isso proporciona subjacente TaskScheduler do objeto a chance de adicionar, alterar ou remover threads que o loop de serviço.This gives the underlying TaskScheduler object the chance to add, change, or remove threads that service the loop.

Se fromInclusive é maior que ou igual a toExclusive, em seguida, o método retornará imediatamente sem executar qualquer iterações.If fromInclusive is greater than or equal to toExclusive, then the method returns immediately without performing any iterations.

Veja também

For<TLocal>(Int32, Int32, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int32, Int32, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int32, Int32, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int32, Int32, Func<TLocal>, Func<Int32,ParallelLoopState,TLocal,TLocal>, Action<TLocal>)

Executa um loop for (For no Visual Basic) com os dados locais de thread no qual as iterações podem ser executadas em paralelo e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop with thread-local data in which iterations may run in parallel, and the state of the loop can be monitored and manipulated.

public:
generic <typename TLocal>
 static System::Threading::Tasks::ParallelLoopResult For(int fromInclusive, int toExclusive, Func<TLocal> ^ localInit, Func<int, System::Threading::Tasks::ParallelLoopState ^, TLocal, TLocal> ^ body, Action<TLocal> ^ localFinally);
public static System.Threading.Tasks.ParallelLoopResult For<TLocal> (int fromInclusive, int toExclusive, Func<TLocal> localInit, Func<int,System.Threading.Tasks.ParallelLoopState,TLocal,TLocal> body, Action<TLocal> localFinally);
static member For : int * int * Func<'Local> * Func<int, System.Threading.Tasks.ParallelLoopState, 'Local, 'Local> * Action<'Local> -> System.Threading.Tasks.ParallelLoopResult
Public Shared Function For(Of TLocal) (fromInclusive As Integer, toExclusive As Integer, localInit As Func(Of TLocal), body As Func(Of Integer, ParallelLoopState, TLocal, TLocal), localFinally As Action(Of TLocal)) As ParallelLoopResult

Parâmetros de tipo

TLocal

O tipo dos dados locais do thread.The type of the thread-local data.

Parâmetros

fromInclusive
Int32 Int32 Int32 Int32

O índice inicial, inclusivo.The start index, inclusive.

toExclusive
Int32 Int32 Int32 Int32

O índice final, exclusivo.The end index, exclusive.

localInit
Func<TLocal>

O delegado da função que retorna o estado inicial dos dados locais para cada tarefa.The function delegate that returns the initial state of the local data for each task.

body
Func<Int32,ParallelLoopState,TLocal,TLocal>

O delegado invocado uma vez por iteração.The delegate that is invoked once per iteration.

localFinally
Action<TLocal>

O delegado que executa uma ação final no estado local de cada tarefa.The delegate that performs a final action on the local state of each task.

Retornos

Uma estrutura que contém informações sobre qual parte do loop foi concluída.A structure that contains information about which portion of the loop completed.

Exceções

O argumento body é null.The body argument is null.

- ou --or- O argumento localInit é null.The localInit argument is null.

- ou --or- O argumento localFinally é null.The localFinally argument is null.

A exceção que contém todas as exceções individuais lançadas em todos os threads.The exception that contains all the individual exceptions thrown on all threads.

Comentários

O body delegado é invocado uma vez para cada valor no intervalo de iteração (fromInclusive, toExclusive).The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). Ele é fornecido com os seguintes parâmetros: a contagem de iteração (Int32), um ParallelLoopState instância que pode ser usada para interromper o loop prematuramente e alguns estados de locais que podem ser compartilhados entre as iterações que executam no mesmo thread.It is provided with the following parameters: the iteration count (Int32), a ParallelLoopState instance that may be used to break out of the loop prematurely, and some local state that may be shared amongst iterations that execute on the same thread.

O localInit delegado é invocado uma vez para cada tarefa que participa de execução do loop e retorna o estado local inicial para cada uma dessas tarefas.The localInit delegate is invoked once for each task that participates in the loop's execution and returns the initial local state for each of those tasks. Esses estados iniciais são passados para o primeiro body invocações em cada tarefa.These initial states are passed to the first body invocations on each task. Em seguida, cada invocação subsequente corpo retorna um valor de estado possivelmente modificado que é passado para a próxima invocação de corpo.Then, every subsequent body invocation returns a possibly modified state value that is passed to the next body invocation. Por fim, a última chamada do corpo em cada tarefa retorna um valor de estado que é passado para o localFinally delegar.Finally, the last body invocation on each task returns a state value that is passed to the localFinally delegate. O localFinally delegado é invocado uma vez por tarefa para executar uma ação final no estado local de cada tarefa.The localFinally delegate is invoked once per task to perform a final action on each task's local state. Esse delegado pode ser invocado simultaneamente em várias tarefas; Portanto, você deve sincronizar o acesso a quaisquer variáveis compartilhadas.This delegate might be invoked concurrently on multiple tasks; therefore, you must synchronize access to any shared variables.

O Parallel.For método pode usar tarefas mais do que os threads durante a vida útil de sua execução, como as tarefas existentes são concluídas e são substituídas por novas tarefas.The Parallel.For method may use more tasks than threads over the lifetime of its execution, as existing tasks complete and are replaced by new tasks. Isso proporciona subjacente TaskScheduler do objeto a chance de adicionar, alterar ou remover threads que o loop de serviço.This gives the underlying TaskScheduler object the chance to add, change, or remove threads that service the loop.

Se fromInclusive é maior que ou igual a toExclusive, em seguida, o método retornará imediatamente sem executar qualquer iterações.If fromInclusive is greater than or equal to toExclusive, then the method returns immediately without performing any iterations.

Para obter um exemplo que usa esse método, consulte como: Escrever um Loop Parallel. for com variáveis locais de Thread.For an example that uses this method, see How to: Write a Parallel.For Loop with Thread-Local Variables.

Veja também

For<TLocal>(Int64, Int64, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int64, Int64, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int64, Int64, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>) For<TLocal>(Int64, Int64, Func<TLocal>, Func<Int64,ParallelLoopState,TLocal,TLocal>, Action<TLocal>)

Executa um loop for (For no Visual Basic) com índices de 64 bits e dados locais de thread no qual as iterações podem ser executadas em paralelo e o estado do loop pode ser monitorado e manipulado.Executes a for (For in Visual Basic) loop with 64-bit indexes and thread-local data in which iterations may run in parallel, and the state of the loop can be monitored and manipulated.

public:
generic <typename TLocal>
 static System::Threading::Tasks::ParallelLoopResult For(long fromInclusive, long toExclusive, Func<TLocal> ^ localInit, Func<long, System::Threading::Tasks::ParallelLoopState ^, TLocal, TLocal> ^ body, Action<TLocal> ^ localFinally);
public static System.Threading.Tasks.ParallelLoopResult For<TLocal> (long fromInclusive, long toExclusive, Func<TLocal> localInit, Func<long,System.Threading.Tasks.ParallelLoopState,TLocal,TLocal> body, Action<TLocal> localFinally);
static member For : int64 * int64 * Func<'Local> * Func<int64, System.Threading.Tasks.ParallelLoopState, 'Local, 'Local> * Action<'Local> -> System.Threading.Tasks.ParallelLoopResult
Public Shared Function For(Of TLocal) (fromInclusive As Long, toExclusive As Long, localInit As Func(Of TLocal), body As Func(Of Long, ParallelLoopState, TLocal, TLocal), localFinally As Action(Of TLocal)) As ParallelLoopResult

Parâmetros de tipo

TLocal

O tipo dos dados locais do thread.The type of the thread-local data.

Parâmetros

fromInclusive
Int64 Int64 Int64 Int64

O índice inicial, inclusivo.The start index, inclusive.

toExclusive
Int64 Int64 Int64 Int64

O índice final, exclusivo.The end index, exclusive.

localInit
Func<TLocal>

O delegado da função que retorna o estado inicial dos dados locais para cada tarefa.The function delegate that returns the initial state of the local data for each task.

body
Func<Int64,ParallelLoopState,TLocal,TLocal>

O delegado invocado uma vez por iteração.The delegate that is invoked once per iteration.

localFinally
Action<TLocal>

O delegado que executa uma ação final no estado local de cada tarefa.The delegate that performs a final action on the local state of each task.

Retornos

Uma estrutura que contém informações sobre qual parte do loop foi concluída.A structure that contains information about which portion of the loop completed.

Exceções

O argumento body é null.The body argument is null.

- ou --or- O argumento localInit é null.The localInit argument is null.

- ou --or- O argumento localFinally é null.The localFinally argument is null.

A exceção que contém todas as exceções individuais lançadas em todos os threads.The exception that contains all the individual exceptions thrown on all threads.

Comentários

O body delegado é invocado uma vez para cada valor no intervalo de iteração (fromInclusive, toExclusive).The body delegate is invoked once for each value in the iteration range (fromInclusive, toExclusive). Ele é fornecido com os seguintes parâmetros: a contagem de iteração (Int64), um ParallelLoopState instância que pode ser usada para interromper o loop prematuramente e alguns estados de locais que podem ser compartilhados entre as iterações que são executados na mesma tarefa.It is provided with the following parameters: the iteration count (Int64), a ParallelLoopState instance that may be used to break out of the loop prematurely, and some local state that may be shared amongst iterations that execute on the same task.

O localInit delegado é invocado uma vez para cada tarefa que participa de execução do loop e retorna o estado local inicial para cada uma dessas tarefas.The localInit delegate is invoked once for each task that participates in the loop's execution and returns the initial local state for each of those tasks. Esses estados iniciais são passados para o primeiro body invocações em cada tarefa.These initial states are passed to the first body invocations on each task. Em seguida, cada invocação subsequente corpo retorna um valor de estado possivelmente modificado que é passado para a próxima invocação de corpo.Then, every subsequent body invocation returns a possibly modified state value that is passed to the next body invocation. Por fim, a última chamada do corpo em cada tarefa retorna um valor de estado que é passado para o localFinally delegar.Finally, the last body invocation on each task returns a state value that is passed to the localFinally delegate. O localFinally delegado é invocado uma vez por tarefa para executar uma ação final no estado local de cada tarefa.The localFinally delegate is invoked once per task to perform a final action on each task's local state. Esse delegado pode ser invocado simultaneamente em várias tarefas; Portanto, você deve sincronizar o acesso a quaisquer variáveis compartilhadas.This delegate might be invoked concurrently on multiple tasks; therefore, you must synchronize access to any shared variables.

O Parallel.For método pode usar tarefas mais do que os threads durante a vida útil de sua execução, como as tarefas existentes são concluídas e são substituídas por novas tarefas.The Parallel.For method may use more tasks than threads over the lifetime of its execution, as existing tasks complete and are replaced by new tasks. Isso proporciona subjacente TaskScheduler do objeto a chance de adicionar, alterar ou remover threads que o loop de serviço.This gives the underlying TaskScheduler object the chance to add, change, or remove threads that service the loop.

Se fromInclusive é maior que ou igual a toExclusive, em seguida, o método retornará imediatamente sem executar qualquer iterações.If fromInclusive is greater than or equal to toExclusive, then the method returns immediately without performing any iterations.

Para obter um exemplo que usa esse método, consulte como: Escrever um Loop Parallel. for com variáveis locais de Thread.For an example that uses this method, see How to: Write a Parallel.For Loop with Thread-Local Variables.

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Aplica-se a