本文整理汇总了C#中System.Threading.Tasks.Parallel.For方法的典型用法代码示例。如果您正苦于以下问题：C# Parallel.For方法的具体用法？C# Parallel.For怎么用？C# Parallel.For使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类System.Threading.Tasks.Parallel的用法示例。
在下文中一共展示了Parallel.For方法的6个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C#代码示例。
示例1: Main
//引入命名空间
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.");
}
}输出：
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
示例2: Main
//引入命名空间
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示例3: CancelDemo
//引入命名空间
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();
}
}
}示例4: Main
//引入命名空间
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);
}
}
}示例5: Main
//引入命名空间
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;
}
}
}
}示例6: Main
//引入命名空间
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;
}
}