我如何报告另一个班级的背景工作者做的工作？

Question

我想以百分比报告进度，并通过文本告诉用户，例如“正在构建地图，请稍候...”

在 form1 中，我有所有 backgroundworker1 事件。并且已经将 WorkerReportsProgress 设置为 true，并将 WorkerSupportsCancellation 设置为 true。

我从工具箱将它添加到设计器的后台工作人员。

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            if (backgroundWorker1.CancellationPending == true)
            {
                e.Cancel = true;
                return; // this will fall to the finally and close everything    
            }
            else
            {
                ExtractImages ei = new ExtractImages();
                ei.Init();
            }
        }

        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {

        }

        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {

        }

以及要报告的班级：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Net;
using System.Xml;
using HtmlAgilityPack;

namespace SatelliteImages
{
    class ExtractImages
    {
        static WebClient client;
        static string htmltoextract;
        public static List<string> countriescodes = new List<string>();
        public static List<string> countriesnames = new List<string>();
        public static List<string> DatesAndTimes = new List<string>();
        public static List<string> imagesUrls = new List<string>();
        static string firstUrlPart = "http://www.sat24.com/image2.ashx?region=";
        static string secondUrlPart = "&time=";
        static string thirdUrlPart = "&ir=";

        public void Init()
        {
            ExtractCountires();
            foreach (string cc in countriescodes)
            {
                ExtractDateAndTime("http://www.sat24.com/image2.ashx?region=" + cc);
            }
            ImagesLinks();
        }

        public static void ExtractCountires()
        {
            try
            {
                htmltoextract = "http://sat24.com/en/?ir=true";//"http://sat24.com/en/";// + regions;
                client = new WebClient();
                client.DownloadFile(htmltoextract, @"c:\temp\sat24.html");
                client.Dispose();

                string tag1 = "<li><a href=\"/en/";
                string tag2 = "</a></li>";

                string s = System.IO.File.ReadAllText(@"c:\temp\sat24.html");
                s = s.Substring(s.IndexOf(tag1));
                s = s.Substring(0, s.LastIndexOf(tag2) + tag2.ToCharArray().Length);
                s = s.Replace("\r", "").Replace("\n", "").Replace(" ", "");

                string[] parts = s.Split(new string[] { tag1, tag2 }, StringSplitOptions.RemoveEmptyEntries);


                string tag3 = "<li><ahref=\"/en/";

                for (int i = 0; i < parts.Length; i++)
                {
                    if (i == 17)
                    {
                        //break;
                    }
                    string l = "";
                    if (parts[i].Contains(tag3))
                        l = parts[i].Replace(tag3, "");

                    string z1 = l.Substring(0, l.IndexOf('"'));
                    if (z1.Contains("</ul></li><liclass="))
                    {
                        z1 = z1.Replace("</ul></li><liclass=", "af");
                    }
                    countriescodes.Add(z1);
                    countriescodes.GroupBy(n => n).Any(c => c.Count() > 1);

                    string z2 = parts[i].Substring(parts[i].LastIndexOf('>') + 1);
                    if (z2.Contains("&amp;"))
                    {
                        z2 = z2.Replace("&amp;", " & ");
                    }
                    countriesnames.Add(z2);
                    countriesnames.GroupBy(n => n).Any(c => c.Count() > 1);
                }
            }
            catch (Exception e)
            {

            }
        }

        public void ExtractDateAndTime(string baseAddress)
        {
            try
            {
                var wc = new WebClient();
                wc.BaseAddress = baseAddress;
                HtmlDocument doc = new HtmlDocument();

                var temp = wc.DownloadData("/en");
                doc.Load(new MemoryStream(temp));

                var secTokenScript = doc.DocumentNode.Descendants()
                    .Where(e =>
                           String.Compare(e.Name, "script", true) == 0 &&
                           String.Compare(e.ParentNode.Name, "div", true) == 0 &&
                           e.InnerText.Length > 0 &&
                           e.InnerText.Trim().StartsWith("var region")
                          ).FirstOrDefault().InnerText;
                var securityToken = secTokenScript;
                securityToken = securityToken.Substring(0, securityToken.IndexOf("arrayImageTimes.push"));
                securityToken = secTokenScript.Substring(securityToken.Length).Replace("arrayImageTimes.push('", "").Replace("')", "");
                var dates = securityToken.Trim().Split(new string[] { ";" }, StringSplitOptions.RemoveEmptyEntries);
                var scriptDates = dates.Select(x => new ScriptDate { DateString = x });
                foreach (var date in scriptDates)
                {
                    DatesAndTimes.Add(date.DateString);
                }
            }
            catch
            {
                countriescodes = new List<string>();
                countriesnames = new List<string>();
                DatesAndTimes = new List<string>();
                imagesUrls = new List<string>();
                this.Init();
            }
        }

        public class ScriptDate
        {
            public string DateString { get; set; }
            public int Year
            {
                get
                {
                    return Convert.ToInt32(this.DateString.Substring(0, 4));
                }
            }
            public int Month
            {
                get
                {
                    return Convert.ToInt32(this.DateString.Substring(4, 2));
                }
            }
            public int Day
            {
                get
                {
                    return Convert.ToInt32(this.DateString.Substring(6, 2));
                }
            }
            public int Hours
            {
                get
                {
                    return Convert.ToInt32(this.DateString.Substring(8, 2));
                }
            }
            public int Minutes
            {
                get
                {
                    return Convert.ToInt32(this.DateString.Substring(10, 2));
                }
            }
        }

        public void ImagesLinks()
        {
            int cnt = 0;
            foreach (string countryCode in countriescodes)
            {
                cnt++;
                for (; cnt < DatesAndTimes.Count(); cnt++)
                {
                    string imageUrl = firstUrlPart + countryCode + secondUrlPart + DatesAndTimes[cnt] + thirdUrlPart + "true";
                    imagesUrls.Add(imageUrl);
                    if (cnt % 10 == 0) break;
                }
            }
        }
    }
}

在课程中，我想从 Init() 报告它工作的每个国家/地区的名称。因此，例如，在标签上的表单上的 form1 中，当它在 Init() 内的循环中时，它将报告当前正在工作的国家/地区的进度

然后在完成国家/地区后继续报告同一标签，在标签上写下“正在构建地图链接，请稍候...”

所有这些都报告给后台worker progresschanged 事件中的progressBar 作为整体工作。从 0 到 100%。

这是完整的 form1 代码。今天我正在使用 webclient 事件来下载和报告图像的进度。所以也许我应该以某种方式将它与类而不是 backgroundworker 一起使用？还是使用任务 async 和 await ？不确定。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;
using System.Net;
using System.Threading;
using System.Diagnostics;

namespace SatelliteImages
{
    public partial class Form1 : Form
    {
        WebClient webClient;               // Our WebClient that will be doing the downloading for us
        Stopwatch sw = new Stopwatch();    // The stopwatch which we will be using to calculate the download speed
        int count = 0;
        PictureBoxBigSize pbbs;

        public Form1()
        {
            InitializeComponent();

            backgroundWorker1.RunWorkerAsync();
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void btnDownload_Click(object sender, EventArgs e)
        {
            //DownloadFile(ExtractImages.imagesUrls[count], @"C:\Temp\TestingSatelliteImagesDownload\" + count + ".jpg");
            // http://download.thinkbroadband.com/1GB.zip
            DownloadFile("http://download.thinkbroadband.com/1GB.zip", @"C:\Temp\TestingSatelliteImagesDownload\" + "1GB.zip");
        }

        public void DownloadFile(string urlAddress, string location)
        {
            using (webClient = new WebClient())
            {
                webClient.DownloadFileCompleted += new AsyncCompletedEventHandler(Completed);
                webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler(ProgressChanged);

                // The variable that will be holding the url address (making sure it starts with http://)
                Uri URL = urlAddress.StartsWith("http://", StringComparison.OrdinalIgnoreCase) ? new Uri(urlAddress) : new Uri("http://" + urlAddress);

                // Start the stopwatch which we will be using to calculate the download speed
                sw.Start();
                //Thread.Sleep(50);
                txtFileName.Text = count + ".jpg";
                try
                {
                    // Start downloading the file
                    webClient.DownloadFileAsync(URL, location);
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }
        }

        // The event that will fire whenever the progress of the WebClient is changed
        private void ProgressChanged(object sender, DownloadProgressChangedEventArgs e)
        {
            // Calculate download speed and output it to labelSpeed.
            Label2.Text = string.Format("{0} kb/s", (e.BytesReceived / 1024d / sw.Elapsed.TotalSeconds).ToString("0.00"));

            // Update the progressbar percentage only when the value is not the same.
            ProgressBar1.Value = e.ProgressPercentage;

            // Show the percentage on our label.
            Label4.Text = e.ProgressPercentage.ToString() + "%";

            // Update the label with how much data have been downloaded so far and the total size of the file we are currently downloading
            Label5.Text = string.Format("{0} MB's / {1} MB's",
                (e.BytesReceived / 1024d / 1024d).ToString("0.00"),
                (e.TotalBytesToReceive / 1024d / 1024d).ToString("0.00"));
        }

        // The event that will trigger when the WebClient is completed
        private void Completed(object sender, AsyncCompletedEventArgs e)
        {
            // Reset the stopwatch.
            sw.Reset();

            if (e.Cancelled == true)
            {
                MessageBox.Show("Download has been canceled.");
            }
            else
            {

                count++;
                DownloadFile(ExtractImages.imagesUrls[count], @"C:\Temp\TestingSatelliteImagesDownload\" + count + ".jpg");
            }
        }

        private void pictureBox1_MouseEnter(object sender, EventArgs e)
        {
            // 845, 615
            pbbs = new PictureBoxBigSize();
            pbbs.GetImages(pictureBox1);
            pbbs.Show();
        }

主要目标是首先使课程工作取得进展，并向 form1 progressBar 和 label/s 报告有关它当前正在处理的国家名称以及创建地图和链接的总体进度的所有内容。然后报告每个文件下载。因此，现在使用 webclient 可以很好地报告每个图像的下载。但是类中的第一个操作我不知道如何将它与 form1 结合起来。

Answer 1

要向后台工作人员报告进度，您必须致电 backgroundWorker1.ReportProgress(...);

并提供适当的ProgressChangedEventArgs。

您的班级ExtractImages 实际上与后台工作人员无关。它的目的是提取图像，我认为不应该将后台工作人员作为参数来进行上述调用。相反，我建议在它取得进展时给它一个事件让它自己发起：

class ExtractImages
{
    // shortened

    // inherit some EventArgs
    public class ProgressEventArgs : EventArgs
    {
         public int Percentage {get;set;}
         public string StateText {get;set;}
    }

    public event EventHandler<ProgressEventArgs> ProgressChanged;

    public void Init()
    {
        ExtractCountires();
        foreach (string cc in countriescodes)
        {
            // raise event here
            ProgressChanged?.Invoke(new ProgressChangedEventArgs {Percentage = ..., StateText = cc});
            ExtractDateAndTime("http://www.sat24.com/image2.ashx?region=" + cc);
        }
        ImagesLinks();
    }
}

并在您的 DoWork 方法中订阅该事件：

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
    if (backgroundWorker1.CancellationPending == true)
    {
        e.Cancel = true;
        return; // this will fall to the finally and close everything    
    }
    else
    {
        ExtractImages ei = new ExtractImages();
        ei.ProgressChanged += (sender, e) => backgroundWorker1.ReportProgress(e.Percentage, e);
        ei.Init();
    }
}

ProgressEventArgs 可以获取您需要的所有状态信息。 ReportProgress 的第二个参数成为您的 backgroundWorker1_ProgressChanged 处理程序的 ProgressChangedEventArgs 中的 UserState 属性。

---

另一种方法是使用IProgress<T> 接口和Progress<T> 类并将Progress<ProgressChangedArgs> 实例作为参数传递给Init()。