如何从任务内部取消parallel.foreach循环

Question

I have a ImageProcessor class that creates a list of tasks for each of the image providers, inside of these tasks I then run a parallel.foreach loop for all the images for each provider, I want to be able to cancel all the tasks and nested parallel loops from the console, I've found example of how to cancel tasks and how to cancel parallel loops, but I am unsure as how to do it for nested processes.

Below is the code I have at the moment

From my console app:

using (IUnityContainer container = Bootstrapper.Initialise())
            {
                IImageProcessor processor = container.Resolve<IImageProcessor>();

                processor.Container = container;

                try
                {
                    InputArguments arguments = new InputArguments(args);

                    if (arguments.Contains("fs"))
                    {
                        processor.Initialise(arguments["fs"]);
                    }
                    else
                    {
                        processor.Initialise();
                    }

                    processor.Run();

                    Console.WriteLine("\r\n\n\nPress any key to Exit");
                    Console.ReadLine();

                    return (int)ExitCode.Success;
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.Message);

                    Console.WriteLine("\r\n\n\nPress any key to Exit");
                    Console.ReadLine();

                    return (int)ExitCode.UnknownError;
                }
            }

The Run method

public void Run()
        {
            List<Task> tasks = new List<Task>();

            foreach (IFileService fileservice in this.fileServices)
            {
                Task task = Task.Factory.StartNew((arg) =>
                {
                    IFileService fs = (IFileService)arg;

                    string msg = $"Processing {fs.ToString()}...";

                    FileLogger.Write(msg, fs.ToString());
                    ConsoleLogger.WriteLine(msg);
                    fs.ProcessFiles();
                    //fileservice.ReprocessUnMatchedData();
                }, fileservice);

                tasks.Add(task);
            }

            Task.WaitAll(tasks.ToArray());
        }

and inside each file service I have call this method:

protected bool ProcessFileRecord<T>() where T : IDataRecord
        {
            int matched = 0;
            int notMatched = 0;
            int skipped = 0;
            bool result;
            object lockObject = new object();

            try
            {
                processTracker = GetTracker();

                if (databaseHelper.TrackerFullyProcessed(processTracker))
                {
                    LoggingService.Write("File already processed... Skipping.", LoggingTarget.All, serviceName);

                    result = true;
                }

                LoggingService.Write($"\r\nProcessing index file {fileRecord.IndexFileName}", LoggingTarget.File, serviceName);

                Parallel.ForEach(
                    fileRecord.DataRecords,
                    new ParallelOptions() { MaxDegreeOfParallelism = Thread.CurrentThread.ManagedThreadId },
                    (item) =>
                    {
                        switch ((RecordProcessResult)ProcessRecord(item))
                        {
                            case RecordProcessResult.Invalid:
                                break;

                            case RecordProcessResult.Matched:
                                Increment(ref matched);
                                break;

                            case RecordProcessResult.NotMatched:
                                Increment(ref notMatched);
                                break;

                            case RecordProcessResult.Skipped:
                                Increment(ref skipped);
                                break;

                            default:
                                break;
                        }

                        lock (lockObject)
                        {
                            if ((matched + notMatched + skipped) % 100 == 0)
                            {
                                LoggingService.Write($"\tMatched: {matched}\tNot Matched: {notMatched}\tSkipped: {skipped}\t total: {matched + notMatched + skipped}", LoggingTarget.Trace & LoggingTarget.Console, serviceName);
                            }
                        }
                    });

                LoggingService.Write($"Total Lines: {matched + notMatched + skipped} \r\nMatched: {matched} \r\nNot Matched: {notMatched} \r\nSkipped: {skipped}", LoggingTarget.All, serviceName);

                this.databaseHelper.UpdateTracker(this.processTracker, matched, notMatched);

                result = true;
            }
            catch (Exception ex)
            {
                LoggingService.Write($"Error processing data file:{fileRecord.IndexFileName}", LoggingTarget.All, serviceName);

                LoggingService.Write($"{ex.ExceptionTreeAsString()}", LoggingTarget.All, serviceName);

                LoggingService.Write($"Total Lines: {(matched + notMatched + skipped)} \r\nMatched: {matched} \r\nNot Matched: {notMatched} \r\nSkipped: {skipped}", LoggingTarget.All, serviceName);

                this.databaseHelper.UpdateTracker(this.processTracker, matched, notMatched);

                result = false;
            }

            return result;
        }

Thank.

Answer 1

请在此页面上查看示例CancellationTokenSource