一个利用 Parallel.For 并行处理任务，带有进度条（ProgressBar）的 WinForm 实例（下）

接着上一篇：一个利用 Parallel.For 并行处理任务，带有进度条（ProgressBar）的 WinForm 实例（上）

直接贴代码了：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Threading;

using System.Threading.Tasks;

using System.Windows.Forms;

namespace WinFormUI.UIForms

{

    public partial class TaskParallelTestForm : Form

    {

        public TaskParallelTestForm()

        {

            InitializeComponent();

        }

        IEnumerable<int> _data = Enumerable.Range(, );

        Action _cancelWork;

        private void DoWorkItem(

            int[] data,

            int item,

            CancellationToken token,

            Action<int> progressReport,

            ParallelLoopState loopState)

        {

            // observe cancellation

            if (token.IsCancellationRequested)

            {

                loopState.Stop();

                return;

            }

            // simulate a work item

            Thread.Sleep();

            // update progress

            progressReport(item);

        }

        private void btnStart_Click(object sender, EventArgs e)

        {

            // update the UI

            this.btnStart.Enabled = false;

            this.btnStop.Enabled = true;

            Action enableUI = () =>

            {

                // update the UI

                this.btnStart.Enabled = true;

                this.btnStop.Enabled = false;

                this._cancelWork = null;

            };

            Action<Exception> handleError = (ex) =>

            {

                // error reporting

                MessageBox.Show(ex.Message);

            };

            try

            {

                // prepare to handle cancellation

                var cts = new CancellationTokenSource();

                var token = cts.Token;

                this._cancelWork = () =>

                {

                    this.btnStop.Enabled = false;

                    cts.Cancel();

                };

                var data = _data.ToArray();

                var total = data.Length;

                // prepare the progress updates

                this.progressBar1.Value = ;

                this.progressBar1.Minimum = ;

                this.progressBar1.Maximum = total;

                var syncConext = SynchronizationContext.Current;

                Action<int> progressReport = (i) =>

                    syncConext.Post(_ => this.progressBar1.Increment(), null);

                // offload Parallel.For from the UI thread

                // as a long-running operation

                var task = Task.Factory.StartNew(() =>

                {

                    Parallel.For(, total, (item, loopState) =>

                        DoWorkItem(data, item, token, progressReport, loopState));

                    // observe cancellation

                    token.ThrowIfCancellationRequested();

                }, token, TaskCreationOptions.LongRunning, TaskScheduler.Default);

                task.ContinueWith(_ =>

                {

                    try

                    {

                        task.Wait(); // rethrow any error

                    }

                    catch (Exception ex)

                    {

                        while (ex is AggregateException && ex.InnerException != null)

                            ex = ex.InnerException;

                        handleError(ex);

                    }

                    enableUI();

                }, TaskScheduler.FromCurrentSynchronizationContext());

            }

            catch (Exception ex)

            {

                handleError(ex);

                enableUI();

            }

        }

        private void btnStop_Click(object sender, EventArgs e)

        {

            if (this._cancelWork != null)

                this._cancelWork();

        }

    }

}

运行截图：

谢谢浏览！