一个后台工作线程和多个进度条

Question

我想向 WinForm 添加多个进度条，以监控嵌套循环中的三个可能较长的进程。我推测我应该只能使用一个后台工作线程，以下实现是否可以接受：

这是我正在完成工作的班级：

class Class1
    {
        public static void UpdatePB(BackgroundWorker worker)
        {
            for (int i = 1; i <= 10; i++)
            {
                for (int ii = 1; ii <= 10; ii++)
                {
                    for (int iii = 1; iii <= 10; iii++)
                    {
                        Thread.Sleep(10);
                        worker.ReportProgress(iii, "PB3");
                    }
                    Thread.Sleep(10);
                    worker.ReportProgress(ii, "PB2");
                }
                Thread.Sleep(10);
                worker.ReportProgress(i, "PB1");
            }
        }

这里是 backgroundWorker ProgressChanged 事件：

    private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
    {
        // Change the value of the ProgressBar to the BackgroundWorker progress.
        switch (e.UserState.ToString())
        {
            case "PB1":
                progressBar1.Value = e.ProgressPercentage;
                this.label1.Text = e.ProgressPercentage.ToString();
                break;
            case "PB2":
                progressBar2.Value = e.ProgressPercentage;
                this.label2.Text = e.ProgressPercentage.ToString();
                break;
            case "PB3":
                progressBar3.Value = e.ProgressPercentage;
                this.label3.Text = e.ProgressPercentage.ToString();
                break;
        }

        Application.DoEvents();
    }

Answer 1

好的，经过数小时的搜索，我找到了这个LINK，它让我能够弄清楚我做错了什么。基本上，我正在做的是在 BackgroundWorker 线程上运行进度条，同时仍在主 UI 线程上运行进程。我意识到这不是我应该做的，所以我现在在 BackgroundWorker 线程上运行所有内容。此外，您将在我的代码示例中看到，我需要维护两个单独的进度条并使用状态信息更新一个富文本框。我能够很容易地实现这个功能。这是我的最终解决方案：

using System;
using System.ComponentModel;
using System.Windows.Forms;

namespace BackgroundWorkerThreadExample
{
    public partial class Form1 : Form
    {
        public delegate void ProgressUpdatedCallaback(ProgressUpdatedEventArgs progress);
        BackgroundWorker bw = new BackgroundWorker();

        public Form1()
        {
            InitializeComponent();
            bw.WorkerReportsProgress = true;
            bw.WorkerSupportsCancellation = true;
            bw.DoWork += new DoWorkEventHandler(backgroundWorker_DoWork);
            bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(backgroundWorker_RunWorkerCompleted);
        }

        private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
        {
            DatabaseProcessor.ProgressUpdated += new DatabaseProcessor.ProgressUpdatedEvent(ProgressUpdated);
            DatabaseProcessor.GetData();
        }

        private void backgroundWorker_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)
        {
            bw.Dispose();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            bw.RunWorkerAsync();
        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (bw.IsBusy == true)
            {
                bw.CancelAsync();
            }
            bw.Dispose();
        }

        private void ProgressUpdated(ProgressUpdatedEventArgs progressUpdated)
        {
            if (InvokeRequired)
            {
                Invoke(new ProgressUpdatedCallaback(this.UpdateProgress), new object[] { progressUpdated });
            }
            else
            {
                UpdateProgress(progressUpdated);
            }
        }

        private void UpdateProgress(ProgressUpdatedEventArgs args)
        {
            ProgressBar pb = new ProgressBar();
            Label lb = new Label();

            if (args.Message == "")
            {
                if (args.PBNum == 1)
                {
                    pb = progressBar1;
                    lb = label1;
                }
                else if (args.PBNum == 2)
                {
                    pb = progressBar2;
                    lb = label2;
                }

                if (pb.Maximum != args.Total)
                {
                    // initial setup
                    pb.Minimum = 0;
                    pb.Maximum = args.Total;
                    pb.Style = ProgressBarStyle.Continuous;
                }

                pb.Value = args.Processed;

                if (args.Total > 0)
                {
                    double progress = args.Processed / (args.Total * 1.0);
                    lb.Text = progress.ToString("P2");
                }
            }
            else
            {
                this.richTextBox1.Text += args.Message;
                //Goto last line
                this.richTextBox1.SelectionStart = this.richTextBox1.Text.Length;
                this.richTextBox1.ScrollToCaret();
            }
            //Application.DoEvents();
        }
    }

    public static class DatabaseProcessor
    {
        public delegate void ProgressUpdatedEvent(ProgressUpdatedEventArgs progressUpdated);
        public static event ProgressUpdatedEvent ProgressUpdated;

        public static void GetData()
        {
            int total = 126;
            Random randomGenerator = new Random();
            for (int i = 0; i < total; i++)
            {
                // Do some processing here
                double delay = (double)randomGenerator.Next(2) + randomGenerator.NextDouble();
                int sleep = (int)delay * 1000;
                System.Threading.Thread.Sleep(sleep);
                RaiseEvent(1, total, i + 1);
                RaiseEvent(0, 0, 0, string.Format("Processing Item {0} \r\n", i + 1));

                for (int ii = 0; ii < total; ii++)
                {
                    // Do some processing here
                    double delay2 = (double)randomGenerator.Next(2) + randomGenerator.NextDouble();
                    int sleep2 = (int)delay2 * 10;
                    System.Threading.Thread.Sleep(sleep2);
                    RaiseEvent(2, total, ii + 1);
                }
            }
        }

        private static void RaiseEvent(int pbNum, int total, int current, string message = "")
        {
            if (ProgressUpdated != null)
            {
                ProgressUpdatedEventArgs args = new ProgressUpdatedEventArgs(pbNum, total, current, message);
                ProgressUpdated(args);
            }
        }
    }

    public class ProgressUpdatedEventArgs : EventArgs
    {
        public ProgressUpdatedEventArgs(int pbNum, int total, int progress, string message = "")
        {
            this.PBNum = pbNum;
            this.Total = total;
            this.Processed = progress;
            this.Message = message;
        }
        public string Message { get; private set; }
        public int PBNum { get; private set; }

        public int Processed { get; private set; }
        public int Total { get; private set; }
    }
}

Answer 2

嗯，你正在显示一个假的进度条......如果这是你想要的，那么这个通用方法是可以的。这里有两个改进：

1. 不要使用 DoEvents。相反，只需保持 UI 的消息循环畅通。立即处理活动账单。
2. 有些人可能更喜欢在适当的时间间隔内设置一个或三个计时器的解决方案。我认为这会更好，因为您不需要后台线程并且它们更精确。也就是说，我认为您的方法在这种情况下是可读的、可维护的并且通常很好。